From Capper Wiki
The place where it all started and where our Capper Community first assembled, Caption This! (aka Mystery Science Theater 3000 present Caption This! aka CT) was available at SCIFI.com from 10/30/96 (?) to 1/31/04.
Caption This! imitated the style of an old puppet-show-based TV program, long since canceled (sometime last century). It was a comedy sort of show, but not a sitcom, and had been originated by Joel Hodgson and others of Best Brains Inc. in Minnesota. It was called "Mystery Science Theater 3000", commonly abbreviated MST3K.