diff --git a/includes/class-newspack-newsletters-contacts.php b/includes/class-newspack-newsletters-contacts.php
index c87a526c5..29a6f4c04 100644
--- a/includes/class-newspack-newsletters-contacts.php
+++ b/includes/class-newspack-newsletters-contacts.php
@@ -31,10 +31,11 @@ class Newspack_Newsletters_Contacts {
 	 * }
 	 * @param string[]|false $lists   Array of list IDs to subscribe the contact to. If empty or false, contact will be created but not subscribed to any lists.
 	 * @param bool           $async   Whether to add the contact asynchronously. Default is false.
+	 * @param string         $context Context of the update for logging purposes.
 	 *
 	 * @return array|WP_Error|true Contact data if it was added, or error otherwise. True if async.
 	 */
-	public static function upsert( $contact, $lists = false, $async = false ) {
+	public static function upsert( $contact, $lists = false, $async = false, $context = 'Unknown' ) {
 		if ( ! is_array( $lists ) && false !== $lists ) {
 			$lists = [ $lists ];
 		}
@@ -59,7 +60,7 @@ public static function upsert( $contact, $lists = false, $async = false ) {
 		}
 
 		if ( defined( 'NEWSPACK_NEWSLETTERS_ASYNC_SUBSCRIPTION_ENABLED' ) && NEWSPACK_NEWSLETTERS_ASYNC_SUBSCRIPTION_ENABLED && true === $async ) {
-			Newspack_Newsletters_Subscription::add_subscription_intent( $contact, $lists );
+			Newspack_Newsletters_Subscription::add_subscription_intent( $contact, $lists, $context );
 			return true;
 		}
 
@@ -113,17 +114,18 @@ public static function upsert( $contact, $lists = false, $async = false ) {
 		 */
 		$lists = apply_filters( 'newspack_newsletters_contact_lists', $lists, $contact, $provider->service );
 
-		return self::add_to_esp( $contact, $lists, $is_updating );
+		return self::add_to_esp( $contact, $lists, $is_updating, $context );
 	}
 
 	/**
 	 * Permanently delete a user subscription.
 	 *
-	 * @param int $user_id User ID.
+	 * @param int    $user_id User ID.
+	 * @param string $context Context of the update for logging purposes.
 	 *
 	 * @return bool|WP_Error Whether the contact was deleted or error.
 	 */
-	public static function delete( $user_id ) {
+	public static function delete( $user_id, $context = 'Unknown' ) {
 		$user = get_user_by( 'id', $user_id );
 		if ( ! $user ) {
 			return new WP_Error( 'newspack_newsletters_invalid_user', __( 'Invalid user.' ) );
@@ -139,7 +141,24 @@ public static function delete( $user_id ) {
 		if ( ! method_exists( $provider, 'delete_contact' ) ) {
 			return new WP_Error( 'newspack_newsletters_invalid_provider_method', __( 'Provider does not support deleting user subscriptions.' ) );
 		}
-		return $provider->delete_contact( $user->user_email );
+		$result = $provider->delete_contact( $user->user_email );
+
+		do_action(
+			'newspack_log',
+			'newspack_esp_sync_delete_contact',
+			$context,
+			[
+				'type'       => is_wp_error( $result ) ? 'error' : 'debug',
+				'data'       => [
+					'provider' => $provider->service,
+					'errors'   => is_wp_error( $result ) ? $result->get_error_message() : [],
+				],
+				'user_email' => $user->user_email,
+				'file'       => 'newspack_esp_sync',
+			]
+		);
+
+		return $result;
 	}
 
 	/**
@@ -150,10 +169,11 @@ public static function delete( $user_id ) {
 	 *
 	 * @param string   $email Contact email address.
 	 * @param string[] $lists Array of list IDs to subscribe the contact to.
+	 * @param string   $context Context of the update for logging purposes.
 	 *
 	 * @return bool|WP_Error Whether the contact was updated or error.
 	 */
-	public static function update_lists( $email, $lists = [] ) {
+	public static function update_lists( $email, $lists = [], $context = 'Unknown' ) {
 		if ( ! Newspack_Newsletters_Subscription::has_subscription_management() ) {
 			return new WP_Error( 'newspack_newsletters_not_supported', __( 'Not supported for this provider', 'newspack-newsletters' ) );
 		}
@@ -175,7 +195,26 @@ public static function update_lists( $email, $lists = [] ) {
 			return false;
 		}
 
-		$result = $provider->update_contact_lists_handling_local( $email, $lists_to_add, $lists_to_remove );
+		return self::add_and_remove_lists( $email, $lists_to_add, $lists_to_remove, $context );
+	}
+
+	/**
+	 * Add and remove a contact from lists.
+	 *
+	 * @param string   $email          Contact email address.
+	 * @param string[] $lists_to_add    Array of list IDs to subscribe the contact to.
+	 * @param string[] $lists_to_remove Array of list IDs to remove the contact from.
+	 * @param string   $context        Context of the update for logging purposes.
+	 *
+	 * @return bool|WP_Error Whether the contact was updated or error.
+	 */
+	public static function add_and_remove_lists( $email, $lists_to_add = [], $lists_to_remove = [], $context = 'Unknown' ) {
+		if ( ! Newspack_Newsletters_Subscription::has_subscription_management() ) {
+			return new WP_Error( 'newspack_newsletters_not_supported', __( 'Not supported for this provider', 'newspack-newsletters' ) );
+		}
+		$provider = Newspack_Newsletters::get_service_provider();
+
+		$result = $provider->update_contact_lists_handling_local( $email, $lists_to_add, $lists_to_remove, $context );
 
 		/**
 		 * Fires after a contact's lists are updated.
@@ -185,8 +224,26 @@ public static function update_lists( $email, $lists = [] ) {
 		 * @param string[]      $lists_to_add    Array of list IDs to subscribe the contact to.
 		 * @param string[]      $lists_to_remove Array of list IDs to remove the contact from.
 		 * @param bool|WP_Error $result          True if the contact was updated or error if failed.
+		 * @param string        $context         Context of the update for logging purposes.
 		 */
-		do_action( 'newspack_newsletters_update_contact_lists', $provider->service, $email, $lists_to_add, $lists_to_remove, $result );
+		do_action( 'newspack_newsletters_update_contact_lists', $provider->service, $email, $lists_to_add, $lists_to_remove, $result, $context );
+
+		do_action(
+			'newspack_log',
+			'newspack_esp_sync_update_lists',
+			$context,
+			[
+				'type'       => is_wp_error( $result ) ? 'error' : 'debug',
+				'data'       => [
+					'provider'        => $provider->service,
+					'lists_to_add'    => $lists_to_add,
+					'lists_to_remove' => $lists_to_remove,
+					'errors'          => is_wp_error( $result ) ? $result->get_error_messages() : [],
+				],
+				'user_email' => $email,
+				'file'       => 'newspack_esp_sync',
+			]
+		);
 
 		return $result;
 	}
@@ -195,13 +252,14 @@ public static function update_lists( $email, $lists = [] ) {
 	 * Internal method to add a contact to lists. Should be called by the
 	 * `add_contact` method or `handle_async_subscribe` for the async strategy.
 	 *
-	 * @param array $contact     Contact information.
-	 * @param array $lists       Array of list IDs to subscribe the contact to.
-	 * @param bool  $is_updating Whether the contact is being updated. If false, the contact is being created.
+	 * @param array  $contact     Contact information.
+	 * @param array  $lists       Array of list IDs to subscribe the contact to.
+	 * @param bool   $is_updating Whether the contact is being updated. If false, the contact is being created.
+	 * @param string $context    Context of the update for logging purposes.
 	 *
 	 * @return array|WP_Error Contact data if it was added, or error otherwise.
 	 */
-	private static function add_to_esp( $contact, $lists = [], $is_updating = false ) {
+	private static function add_to_esp( $contact, $lists = [], $is_updating = false, $context = 'Unknown' ) {
 		$provider = Newspack_Newsletters::get_service_provider();
 		$errors   = new WP_Error();
 		$result   = [];
@@ -247,8 +305,26 @@ private static function add_to_esp( $contact, $lists = [], $is_updating = false
 		 * @param string[]|false      $lists    Array of list IDs to subscribe the contact to.
 		 * @param array|WP_Error      $result   Array with data if the contact was added or error if failed.
 		 * @param bool                $is_updating Whether the contact is being updated. If false, the contact is being created.
+		 * @param string              $context  Context of the update for logging purposes.
 		 */
-		do_action( 'newspack_newsletters_add_contact', $provider->service, $contact, $lists, $result, $is_updating );
+		do_action( 'newspack_newsletters_add_contact', $provider->service, $contact, $lists, $result, $is_updating, $context );
+
+		do_action(
+			'newspack_log',
+			'newspack_esp_sync_upsert_contact',
+			$context,
+			[
+				'type'       => $errors->has_errors() ? 'error' : 'debug',
+				'data'       => [
+					'provider' => $provider->service,
+					'lists'    => $lists,
+					'contact'  => $contact,
+					'errors'   => $errors->get_error_messages(),
+				],
+				'user_email' => $contact['email'],
+				'file'       => 'newspack_esp_sync',
+			]
+		);
 
 		if ( $errors->has_errors() ) {
 			return $errors;
diff --git a/includes/class-newspack-newsletters-subscription.php b/includes/class-newspack-newsletters-subscription.php
index 8720e095c..85ec0422a 100644
--- a/includes/class-newspack-newsletters-subscription.php
+++ b/includes/class-newspack-newsletters-subscription.php
@@ -357,18 +357,19 @@ public static function get_contact_data( $email_address, $return_details = false
 	 */
 	public static function add_contact( $contact, $lists = false, $async = false ) {
 		_deprecated_function( __METHOD__, '2.21', 'Newspack_Newsletters_Contacts::upsert' );
-		return Newspack_Newsletters_Contacts::upsert( $contact, $lists, $async );
+		return Newspack_Newsletters_Contacts::upsert( $contact, $lists, $async, 'deprecated' );
 	}
 
 	/**
 	 * Register a subscription intent and dispatches a async request to process it.
 	 *
-	 * @param array $contact     Contact information.
-	 * @param array $lists       Array of list IDs to subscribe the contact to.
+	 * @param array  $contact     Contact information.
+	 * @param array  $lists       Array of list IDs to subscribe the contact to.
+	 * @param string $context Context of the update for logging purposes.
 	 *
 	 * @return int|WP_Error Subscription intent ID or error.
 	 */
-	public static function add_subscription_intent( $contact, $lists ) {
+	public static function add_subscription_intent( $contact, $lists, $context = '' ) {
 		$intent_id = \wp_insert_post(
 			[
 				'post_type'   => self::SUBSCRIPTION_INTENT_CPT,
@@ -377,6 +378,7 @@ public static function add_subscription_intent( $contact, $lists ) {
 					'contact' => $contact,
 					'lists'   => $lists,
 					'errors'  => [],
+					'context' => $context,
 				],
 			]
 		);
@@ -422,6 +424,7 @@ private static function get_subscription_intent( $intent_id_or_post ) {
 			'contact' => get_post_meta( $intent->ID, 'contact', true ),
 			'lists'   => get_post_meta( $intent->ID, 'lists', true ),
 			'errors'  => get_post_meta( $intent->ID, 'errors', true ),
+			'context' => get_post_meta( $intent->ID, 'context', true ),
 		];
 	}
 
@@ -473,7 +476,8 @@ public static function process_subscription_intents( $intent_id = null ) {
 			$contact     = $intent['contact'];
 			$email       = $contact['email'];
 			$lists       = $intent['lists'];
-			$result      = Newspack_Newsletters_Contacts::upsert( $contact, $lists, false );
+			$context     = $intent['context'];
+			$result      = Newspack_Newsletters_Contacts::upsert( $contact, $lists, false, $context . ' (ASYNC)' );
 
 			$user = get_user_by( 'email', $email );
 			if ( \is_wp_error( $result ) ) {
@@ -576,13 +580,14 @@ public static function newspack_registered_reader( $email, $authenticate, $user_
 
 		// Adding is actually upserting, so no need to check if the hook is called for an existing user.
 		try {
-			self::add_contact(
+			Newspack_Newsletters_Contacts::upsert(
 				[
 					'email'    => $email,
 					'metadata' => $metadata,
 				],
 				$lists,
-				true // Async.
+				true, // Async.
+				'Reader registration hook on Newsletters plugin'
 			);
 		} catch ( \Exception $e ) {
 			// Avoid breaking the registration process.
@@ -603,7 +608,7 @@ public static function newspack_registered_reader( $email, $authenticate, $user_
 	 */
 	private static function update_contact_lists( $email, $lists = [] ) {
 		_deprecated_function( __METHOD__, '2.21', 'Newspack_Newsletters_Contacts::update_lists' );
-		return Newspack_Newsletters_Contacts::update_lists( $email, $lists );
+		return Newspack_Newsletters_Contacts::update_lists( $email, $lists, 'deprecated' );
 	}
 
 	/**
@@ -1001,7 +1006,7 @@ public static function process_subscription_update() {
 		} else {
 			$email  = get_userdata( get_current_user_id() )->user_email;
 			$lists  = isset( $_POST['lists'] ) ? array_map( 'sanitize_text_field', $_POST['lists'] ) : [];
-			$result = Newspack_Newsletters_Contacts::update_lists( $email, $lists );
+			$result = Newspack_Newsletters_Contacts::update_lists( $email, $lists, 'User updated their subscriptions on My Account page' );
 			if ( is_wp_error( $result ) ) {
 				wc_add_notice( $result->get_error_message(), 'error' );
 			} elseif ( false === $result ) {
diff --git a/includes/plugins/class-woocommerce-memberships.php b/includes/plugins/class-woocommerce-memberships.php
index aeffd1c69..b52b1ce8e 100644
--- a/includes/plugins/class-woocommerce-memberships.php
+++ b/includes/plugins/class-woocommerce-memberships.php
@@ -10,6 +10,7 @@
 use Newspack\Newsletters\Subscription_List;
 use Newspack\Newsletters\Subscription_Lists;
 use Newspack_Newsletters;
+use Newspack_Newsletters_Contacts;
 use Newspack_Newsletters_Logger;
 
 defined( 'ABSPATH' ) || exit;
@@ -206,8 +207,6 @@ public static function remove_user_from_lists( $user_membership ) {
 			return;
 		}
 
-		$provider = Newspack_Newsletters::get_service_provider();
-
 		/**
 		 * Check if the user is already in one of the lists. If they are, store it.
 		 *
@@ -225,10 +224,8 @@ public static function remove_user_from_lists( $user_membership ) {
 
 		self::update_user_lists_on_deactivation( $user->ID, $user_membership->get_id(), $existing_lists );
 
-		if ( ! empty( $provider ) ) {
-			$provider->update_contact_lists_handling_local( $user_email, [], $lists_to_remove );
-			Newspack_Newsletters_Logger::log( 'Reader ' . $user_email . ' removed from the following lists: ' . implode( ', ', $lists_to_remove ) );
-		}
+		Newspack_Newsletters_Contacts::add_and_remove_lists( $user_email, [], $lists_to_remove, 'Removing user from lists tied to Memberships being marked as inactive' );
+		Newspack_Newsletters_Logger::log( 'Reader ' . $user_email . ' removed from the following lists: ' . implode( ', ', $lists_to_remove ) );
 	}
 
 	/**
@@ -336,8 +333,7 @@ public static function add_user_to_lists( $plan, $args ) {
 			return;
 		}
 
-		$provider = Newspack_Newsletters::get_service_provider();
-		$result = $provider->update_contact_lists_handling_local( $user_email, $lists_to_add );
+		$result = Newspack_Newsletters_Contacts::add_and_remove_lists( $user_email, $lists_to_add, [], 'Adding user to lists tied to Memberships being marked as active' );
 
 		if ( is_wp_error( $result ) ) {
 			Newspack_Newsletters_Logger::log( 'An error occured while updating lists for ' . $user_email . ': ' . $result->get_error_message() );
diff --git a/includes/service-providers/class-newspack-newsletters-service-provider.php b/includes/service-providers/class-newspack-newsletters-service-provider.php
index 2f0768539..f19a48091 100644
--- a/includes/service-providers/class-newspack-newsletters-service-provider.php
+++ b/includes/service-providers/class-newspack-newsletters-service-provider.php
@@ -491,12 +491,12 @@ public function add_contact_handling_local_list( $contact, $list_id ) {
 			try {
 				$list = Subscription_List::from_form_id( $list_id );
 				if ( ! $list->is_configured_for_provider( $this->service ) ) {
-					return new WP_Error( 'List not properly configured for the provider' );
+					return new WP_Error( "List $list_id not properly configured for the provider" );
 				}
 				$list_settings = $list->get_provider_settings( $this->service );
 				return $this->add_esp_local_list_to_contact( $contact['email'], $list_settings['tag_id'], $list_settings['list'] );
 			} catch ( \InvalidArgumentException $e ) {
-				return new WP_Error( 'List not found' );
+				return new WP_Error( "List $list_id not found" );
 			}
 		}
 	}
@@ -509,15 +509,16 @@ public function add_contact_handling_local_list( $contact, $list_id ) {
 	 * @param string   $email           Contact email address.
 	 * @param string[] $lists_to_add    Array of list IDs to subscribe the contact to.
 	 * @param string[] $lists_to_remove Array of list IDs to remove the contact from.
+	 * @param string   $context         The context in which the update is being performed. For logging purposes.
 	 *
 	 * @return true|WP_Error True if the contact was updated or error.
 	 */
-	public function update_contact_lists_handling_local( $email, $lists_to_add = [], $lists_to_remove = [] ) {
+	public function update_contact_lists_handling_local( $email, $lists_to_add = [], $lists_to_remove = [], $context = 'Unknown' ) {
 		$contact = $this->get_contact_data( $email );
 		if ( is_wp_error( $contact ) ) {
 			// Create contact.
-			// Use Newspack_Newsletters_Subscription::add_contact to trigger hooks and call add_contact_handling_local_list if needed.
-			$result = Newspack_Newsletters_Subscription::add_contact( [ 'email' => $email ], $lists_to_add );
+			// Use Newspack_Newsletters_Contacts::upsert to trigger hooks and call add_contact_handling_local_list if needed.
+			$result = Newspack_Newsletters_Contacts::upsert( [ 'email' => $email ], $lists_to_add, false, $context );
 			if ( is_wp_error( $result ) ) {
 				return $result;
 			}
diff --git a/includes/service-providers/mailchimp/class-newspack-newsletters-mailchimp-notes.php b/includes/service-providers/mailchimp/class-newspack-newsletters-mailchimp-notes.php
new file mode 100644
index 000000000..4b39051c0
--- /dev/null
+++ b/includes/service-providers/mailchimp/class-newspack-newsletters-mailchimp-notes.php
@@ -0,0 +1,146 @@
+<?php
+/**
+ * Service Provider: Mailchimp Notes Implementation
+ *
+ * @package Newspack
+ */
+
+defined( 'ABSPATH' ) || exit;
+
+use DrewM\MailChimp\MailChimp;
+use Newspack\Newsletters\Subscription_List;
+
+/**
+ * This class adds logging to Mailchimp contacts using Mailchimp Notes.
+ */
+class Newspack_Newsletters_Mailchimp_Notes {
+
+	/**
+	 * Initializes the hooks.
+	 *
+	 * @return void
+	 */
+	public static function init() {
+		add_action( 'newspack_newsletters_add_contact', array( __CLASS__, 'handle_upsert' ), 10, 6 );
+		add_action( 'newspack_newsletters_update_contact_lists', array( __CLASS__, 'handle_update_lists' ), 10, 6 );
+	}
+
+	/**
+	 * Add a note to a contact in Mailchimp, for Audience list they are a part of.
+	 *
+	 * @param string $email The contact email.
+	 * @param array  $lists An array of lists IDs (as they are used in our forms. aka form_id). A list can be an Audience, a tag, a group or a local list.
+	 * @param string $note The note to add.
+	 * @return void
+	 */
+	private static function add_note( $email, $lists, $note ) {
+		$audience_ids = self::extract_audience_ids( $lists );
+		if ( empty( $audience_ids ) ) {
+			return;
+		}
+		$mc = Newspack_Newsletters_Mailchimp::instance();
+		$api      = new Mailchimp( $mc->api_key() );
+		foreach ( $audience_ids as $audience_id ) {
+			$subscriber_hash = Mailchimp::subscriberHash( $email );
+			$api->post(
+				sprintf( 'lists/%s/members/%s/notes', $audience_id, $subscriber_hash ),
+				[
+					'note' => $note,
+				]
+			);
+		}
+	}
+
+	/**
+	 * Extracts the Audience IDs from the list form IDs.
+	 *
+	 * Given a list of lists, we will parse in which audience they belong.
+	 *
+	 * @param array $lists An array of lists IDs (as they are used in our forms. aka form_id). A list can be an Audience, a tag, a group or a local list.
+	 * @return array An array of Audience IDs.
+	 */
+	private static function extract_audience_ids( $lists ) {
+		$mc = Newspack_Newsletters_Mailchimp::instance();
+		$audience_ids = [];
+		foreach ( $lists as $list ) {
+			if ( Subscription_List::is_local_form_id( $list ) ) {
+				continue;
+			}
+			$remote_list_details = $mc->maybe_extract_group_or_tag_list( $list );
+			if ( false !== $remote_list_details ) {
+				$audience_ids[] = $remote_list_details['list_id'];
+				continue;
+			}
+			$audience_ids[] = $list;
+		}
+		return $audience_ids;
+	}
+
+	/**
+	 * Handles the upsert of a contact.
+	 *
+	 * @param string         $provider The provider name.
+	 * @param array          $contact  {
+	 *    Contact information.
+	 *
+	 *    @type string   $email    Contact email address.
+	 *    @type string   $name     Contact name. Optional.
+	 *    @type string[] $metadata Contact additional metadata. Optional.
+	 * }
+	 * @param string[]|false $lists    Array of list IDs to subscribe the contact to.
+	 * @param array|WP_Error $result   Array with data if the contact was added or error if failed.
+	 * @param bool           $is_updating Whether the contact is being updated. If false, the contact is being created.
+	 * @param string         $context  Context of the update for logging purposes.
+	 * @return void
+	 */
+	public static function handle_upsert( $provider, $contact, $lists, $result, $is_updating, $context ) {
+		if ( 'mailchimp' !== $provider ) {
+			return;
+		}
+
+		$lists_string = implode( ', ', $lists );
+		$message = sprintf(
+			/* translators: 1: email address, 2: list IDs */
+			__( 'Contact updated by Newspack from site %1$s. Context: %2$s. Lists added: %3$s', 'newspack-newsletters' ),
+			get_site_url(),
+			$context,
+			$lists_string
+		);
+
+		self::add_note( $contact['email'], $lists, $message );
+	}
+
+	/**
+	 * Handles the update of lists for a contact.
+	 *
+	 * Note that we will add a note even to the lists (audiences) that the contact is being removed from.
+	 *
+	 * @param string        $provider        The provider name.
+	 * @param string        $email           Contact email address.
+	 * @param string[]      $lists_to_add    Array of list IDs to subscribe the contact to.
+	 * @param string[]      $lists_to_remove Array of list IDs to remove the contact from.
+	 * @param bool|WP_Error $result          True if the contact was updated or error if failed.
+	 * @param string        $context         Context of the update for logging purposes.
+	 * @return void
+	 */
+	public static function handle_update_lists( $provider, $email, $lists_to_add, $lists_to_remove, $result, $context ) {
+		if ( 'mailchimp' !== $provider ) {
+			return;
+		}
+
+		$lists_to_add_string = implode( ', ', $lists_to_add );
+		$lists_to_remove_string = implode( ', ', $lists_to_remove );
+
+		$message = sprintf(
+			/* translators: 1: email address, 2: lists added, 3: lists removed */
+			__( 'Contact updated by Newspack. Context: %1$s. Lists added: %2$s. Lists removed: %3$s', 'newspack-newsletters' ),
+			$context,
+			$lists_to_add_string ? $lists_to_add_string : 'none',
+			$lists_to_remove_string ? $lists_to_remove_string : 'none'
+		);
+
+		self::add_note( $email, array_merge( $lists_to_add, $lists_to_remove ), $message );
+	}
+}
+
+Newspack_Newsletters_Mailchimp_Notes::init();
diff --git a/newspack-newsletters.php b/newspack-newsletters.php
index c5137ea52..3bcb91d98 100644
--- a/newspack-newsletters.php
+++ b/newspack-newsletters.php
@@ -40,6 +40,7 @@
 require_once NEWSPACK_NEWSLETTERS_PLUGIN_FILE . '/includes/service-providers/mailchimp/class-newspack-newsletters-mailchimp-controller.php';
 require_once NEWSPACK_NEWSLETTERS_PLUGIN_FILE . '/includes/service-providers/mailchimp/class-newspack-newsletters-mailchimp-cached-data.php';
 require_once NEWSPACK_NEWSLETTERS_PLUGIN_FILE . '/includes/service-providers/mailchimp/class-newspack-newsletters-mailchimp-usage-reports.php';
+require_once NEWSPACK_NEWSLETTERS_PLUGIN_FILE . '/includes/service-providers/mailchimp/class-newspack-newsletters-mailchimp-notes.php';
 require_once NEWSPACK_NEWSLETTERS_PLUGIN_FILE . '/includes/service-providers/constant_contact/class-newspack-newsletters-constant-contact.php';
 require_once NEWSPACK_NEWSLETTERS_PLUGIN_FILE . '/includes/service-providers/constant_contact/class-newspack-newsletters-constant-contact-controller.php';
 require_once NEWSPACK_NEWSLETTERS_PLUGIN_FILE . '/includes/service-providers/constant_contact/class-newspack-newsletters-constant-contact-sdk.php';
diff --git a/src/blocks/subscribe/index.php b/src/blocks/subscribe/index.php
index 298f6b88c..5cd0a1bd0 100644
--- a/src/blocks/subscribe/index.php
+++ b/src/blocks/subscribe/index.php
@@ -505,7 +505,8 @@ function process_form() {
 			'metadata' => $metadata,
 		],
 		$lists,
-		true // Async.
+		true, // Async.
+		'User subscribed via Newsletters Subscription block'
 	);
 
 	/**
diff --git a/tests/mocks/class-mailchimp-mock.php b/tests/mocks/class-mailchimp-mock.php
index 7d940b6d2..253fd82e9 100644
--- a/tests/mocks/class-mailchimp-mock.php
+++ b/tests/mocks/class-mailchimp-mock.php
@@ -193,5 +193,15 @@ function( $tag_name ) {
 			'status' => 200,
 		];
 	}
+
+	/**
+	 * Get the subscriber hash.
+	 *
+	 * @param string $email Email address.
+	 * @return string
+	 */
+	public static function subscriberHash( $email ) { // phpcs:ignore WordPress.NamingConventions.ValidFunctionName.MethodNameInvalid
+		return md5( strtolower( $email ) );
+	}
 }
 MailChimp::init();
diff --git a/tests/test-subscription-attempts.php b/tests/test-subscription-attempts.php
index 3b6a09ba6..f83def655 100644
--- a/tests/test-subscription-attempts.php
+++ b/tests/test-subscription-attempts.php
@@ -34,14 +34,14 @@ public function test_subscription_attempts_add_and_update() {
 		self::assertEquals( implode( ',', $lists ), $result->list_ids );
 
 		$lists_added = [ 'list3', 'list4' ];
-		do_action( 'newspack_newsletters_update_contact_lists', 'some_esp', $contact['email'], $lists_added, [], true );
+		do_action( 'newspack_newsletters_update_contact_lists', 'some_esp', $contact['email'], $lists_added, [], true, 'test' );
 
 		$result = Newspack_Newsletters_Subscription_Attempts::get_by_email( $contact['email'] );
 		$lists_expected = array_merge( $lists, $lists_added );
 		self::assertEquals( implode( ',', $lists_expected ), $result->list_ids );
 
 		$lists_removed = [ 'list1', 'list3' ];
-		do_action( 'newspack_newsletters_update_contact_lists', 'some_esp', $contact['email'], [], $lists_removed, true );
+		do_action( 'newspack_newsletters_update_contact_lists', 'some_esp', $contact['email'], [], $lists_removed, true, 'test' );
 
 		$result = Newspack_Newsletters_Subscription_Attempts::get_by_email( $contact['email'] );
 		$lists_expected = [ 'list2', 'list4' ];