Add note about anonymous profiles to readme (#127)

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Co-authored-by: Evan Masseau <>

README.md

@@ -158,6 +158,11 @@ Klaviyo.setEmail("[email protected]")
     .setProfileAttribute(ProfileKey.FIRST_NAME, "Robin")
 ```
 
+### Anonymous Tracking
+Klaviyo will track unidentified users with an autogenerated ID whenever a push token is set or an event is created.
+That way, you can collect push tokens and track events prior to collecting profile identifiers such as email or
+phone number. When an identifier is provided, Klaviyo will merge the anonymous user with an identified user.
+
 ## Event Tracking
 The SDK also provides tools for tracking analytics events via the
 [Create Client Event API](https://developers.klaviyo.com/en/reference/create_client_event).