I was making some more improvements to DailyKos this evening while I was putting my daughter to bed, and one of the things I did was fix the caching stuff with a function that returns a UID from the nick provided. Unfortunately, while I was doing this, I managed to make a little mistake and leave a ~ out. To wit:
$snick = s/ /_/g;
vs.
$snick =~ s/ /_/g;
While I of course tested this out on my dev box here at home, I managed to overlook it because I'm the only person who's ever on that box, and sometimes stuff won't turn up there that turns up on the live site. Because of that lack of tilde, everyone was getting the same uid returned when that function ran. It was only like that for about 10-15 minutes, but as far as I can tell everyone noticed.
My apologies for screwing up so royally, and thank you for your kind patience. We're fine now.