Nice idea. Can’t really wait on the web to adopt sane password practices so the pragmatic idea is to consolidate knowledge for the biggest websites.

See if any of your passwords has been seen in a previous security breach.
There's a good chance that 1Password will integrate this into their excellent password manager.

With all the recen high profile hacking going on, I'm seriously thinking about recreating all my passwords somewhat they are unique and unguessable.