Full marks for getting to the core of what I was asking. It seems almost like a year ago nobody had heard of github; and now there are people who don't seem to have heard of anything else.

Not to take away from GitHub being good, but I'm asking what makes it seems that good.

I put a new code on Github and it seems all right. But I'm not going to move code that's been hosted elsewhere for several years even if something slightly better comes along. Consistency is a virtue.