Rabin fingerprinting is not currently used

[bnewbold]

This seems to cause frequent confusion. Eg, here's recent stackoverflow post:

https://stackoverflow.com/questions/51587833/can-dat-protocol-efficiently-support-live-streaming-of-video

I think "How Dat Works" should be updated, but I don't have a patch at this time.

[Frando]

Also, under "How is Dat different than IPFS?", it says:

IPFS and Dat share a number of underlying similarities but address different problems. Both deduplicate content-addressed pieces of data and have a mechanism for searching for peers who have a specific piece of data.

This should be reworded, as it is not true. Dat does not currently deduplicate data, and is not content-addressed, and does not really have a "mechanism for searching for peers who have a specific piece of data".