I found the info on how to use Bitzi in the Changelog for 2.5.0 beta.

Bitzi metadata lookup allows you to get more information about files -- right click in the search and library tabs to try it!.

I've take some time to update some files on the Bitzi site, using their Bitcollider. I guess there aren't yet many checksums on files there, but it's a start.
I'm taking the time to Bitcollide all my shared files. Like the Monty Python's Killer Rabbit or Monty Python's Flying Circus.