How many closets are there?

"Coming out of the closet" has been the popular way of saying "I just told everyone I'm gay" since forever. But now another group is taking up the metaphor: atheists. The Out Campaign not only takes up the closet, the use the Scarlet Letter as their logo. Using sex plus homo coolness to sell your product...I have to give them credit, that's a better ad campaign than organized religion has these days.

This begs the question: just how many closets are there? Or is it one big undifferentiated closet for all people who have aspects to themselves they don't want to share with the public? That would be one crowded, awkward closet. I can just imagine the conversations...

A: "Why are you in here?"
B: "Well, I just found Jesus/Buddha/Mohammad/the Big Spaghetti Monster but I'm not really comfortable talking about it with the friends and family yet. They really don't do the whole religion thing"
A: "Oh...I'm an atheist living in a highly religious small town and I fear persecution if I tell everyone my beliefs"
(awkward silence)
Actual homosexual: What the hell are you people doing in my closet?

P.S. This doesn't preclude atheists from admittance into The Closet. Just straight ones.