At the same time we are being warned against common passwords across multiple accounts, sites (including, ironically Gawker (Gizmodo) who published some of that information) are forcing users to access the sites through amagalmated sign-ons, like Facebook, Disqus, Google which completely violate that principle.

The single identities add another risk because they share a common account ID across multiple sites, seemingly unrelated postings in different contexts could be used to gather a significant amount of 'leaked' personal information even without hacking their identity.