My Steam account seems to have been hijacked. I was invited to join a steam group by another user in Videosift's Steam group. The link he sent was this: http://steamcommunitygroups.awardspace.co.uk/. After entering my account info in the (now clearly bogus) info boxes, seconds later my account's password, secret answer and secret question had been changed, and not by me.

His username was along the lines of Polska something, so be on the lookout for bad links.