I think an atheist community, as you describe it, would be akin to a philosopher-community. Rather than discussing how God makes the world work, like a religious community, an atheist community would likely discuss how the world works without one.[spoiler]Does that make sense? I feel like it doesn't make sense.[/spoiler]

People that discuss how the world works are scientists. I'm an atheist but I'm an engineer, not a scientist. Literally the only thing atheists have in common is lack of belief in god/s. In that way there is no doctrine, no authority, no real organisation. On the other hand, there are societies and clubs, as we all like to hang out with like minded people. So I'd say the answer is both yes and no, depending on what you mean by 'community'.

Except that atheism really isn't much of a philosophy. It's simply the denial of the existence of a deity. There is no set of beliefs for atheism like there is for a religion. Atheists are diverse and believe in all kinds of different things, just not a deity. Now something like nihilism, which I think many atheists at least partially subscribe to, is something that could be discussed at more length as a philosophy.

[spoiler]Why does everyone say you're a bitch? You're not mean at all[/spoiler]