"Atheism is a religion"
"Atheism is not a religion"
There are arguments for both of these views, really.
You can argue that its the lack of religion, though you could also argue that, using the broadest definitions of religion, such as "a cause, principle, or system of beliefs held to with ardor and faith" (http://www.merriam-webster.com/dictionary/religion) that it is a religion. Its a bit of a stretch, but it could fit. Regardless, it is a religious stance or perhaps, to word that better, a stance on religion.
Its not really that big a deal if someone calls it a religion or not though, is it?
EDIT: I am legitimately surprised at the number of atheists here. Interesting. I was actually expecting it to be dominantly Christian like most of the world. Once more people have voted, It'll be interesting to analyze the results and see if any is still dominant. If atheism or any other choice for that matter is strongly dominant it'd be cool to try and analyze this and figure out what it means about furries, or at the very least, FAF.