Well it seems to be a good place to meet and chat with other Atheists for one, we do not exactly have a church to go to for such things.
Im also interested in religious texts, my view is that if God did not write them, then man did (or woman), and contained within these books are much real knowledge and things of moral and ethical worth.
If we are to improve mans lot in this universe we have to look to all sources past, resent and future, the book of proverbs for example contains much good advice, and there are so many others.
And if you like history, to learn about religion is a must, im not so sure i like the calling each other bonkers in one way or another very much, but decent debates done with reason are a gold mine of info.
Even if I totally refute anothers perspective I still find it fascinating to see how they reached there conclusions.