"I get the impression LtU has the same effect going on, but with Haskell as the assumed common language."
I took a random selection of over ten LtU threads, and none of them had Haskell examples. Whoops. ^_^
A search for 10 Arc Forum "item" URIs turns up 7 which are part of a thread with sample Arc code and 3 which aren't. This isn't the same statistic, but it is telling. In this hypothetical forum+language design, the forum should be for discussing the language. Kinda insular. :-p