bluntforce - 7:37 am on Jan 13, 2013 (gmt 0)
Blocking is a user interaction stating that the user no longer wants to see results from a given site. That requires the search engine to acknowledge information from the user.
I'm not aware of significant other circumstances where Chrome is sending user information to Google. If you have verification that's being done, it would be very interesting to see.
There's a distinction between an algorithm segmenting sites meeting certain parameters and individuals using blocking data to verify algorithm accuracy.