short for cross-post; i.e., to post the same message/information in more than one location. Frequently used on Livejournal to indicate an entry posted to multiple communities.
The word cried from the rooftops when something you did about 3 years ago that nobody actually gave a damn about is unearthed by some moron and spread around the community.
Guy 1: Wait, you stole my $10 bill?! XPOSED!!!1!
Guy 2: Uh, that was like three years ago, man.