If you've ever registered to comment at any of the following sites:
Gawker.com
Gizmodo
Kotaku
Jalopnik
Lifehacker
Deadspin
Jezebel
io9
Fleshbot
Gawker.tv
Cityfile
Valleywag
...then your username and password were stolen tonight.
I suggest changing your account info ASAP, as those responsible reportedly intend to repost all the account info publicly.