The caption threads are fun! They are a FR staple. But as we have grown, we now get times where the main forum gets overwhelmed by them (not just from Mr. Silverback, but from many). Right now, the status quo is to leave some but when we are getting too many to move most to chat.
I think the idea of taking over a chat topic (such as chat/humor) and making a thread announcing it and instructing people on how to make it into a sidebar might be the way to go. That way the folks who want them front and center will have them on their latest posts page, always, and those who don't, won't.