At least in the "default" stack overflow for software developers; it's supposed to be a question and answer format about narrowly-focused programming topics. Mo

At least in the "default" stack overflow for software developers; it's supposed to be a question and answer format about narrowly-focused programming topics. More philosophical questions are technically off-topic. But, in the case of this post, it's pretty easy to see why Math Overflow would consider it in their best interest to make an exception! (And perhaps have a slightly different banner.) It's easy to forget the amount of moderation that a good internet message board needs. (Just take a look at Dang's hard work on Hacker News.) Unfortunately, there are many people who just don't have the maturity, or discipline, to ask good, topical, questions. Banners like that are a good compromise, IMO, between the need to focus on a particular topic, and allow flexibility for discussions that straddle the line between on and off topic. I think putting up a banner, but still letting the discussion continue, is a good compromise.