What words mean: "atheist"
"I am an atheist."
If I make that declaration to you, what could you say about me? Can you determine my morality? How about my favorite authors? Does it imply a particular political affiliation? What about education level, or shoe size? Does it tell you why I am an atheist?
Nope. If I say "I am an atheist," the only thing it tells you is I wouldn't answer "yes" to questions such as "Do you believe in Allah?", "Do you believe in Zeus?", or "Do you believe in my god: Pele the volcano god?" Full stop. Period. No mas. "I am an atheist" means only that I don't believe in any gods (uppercased, lowercased, or even all caps).
Contrary to popular belief, it does not tell you I am a Socialist, a Communist, or (shudder) a Democrat (I'm none of the above). It does not tell you I read Nietzsche and Freud all day (Nietzsche is too dense and Freud was a lunatic). It does not tell you about my morality or stance on any issue. It does not tell you my shoe size. It does not tell you why I do not hold the gods belief.
I know there are some who work to reinforce the opposite (American Atheists I'm looking at you here). I've met many an online atheist who gasped with horror at the idea that I didn't like John Kerry and that I thought G.W. Bush wasn't Evil Christian Guy, just a World Class Dumbass. And no, I don't like Michael Moore either.
Atheism is not a religion. Just like "theism" is used to label those who believe in one or more gods, "atheism" is a term used to label those who do not have a belief in any gods. This means two atheists do not necessarily have any other beliefs in common. At the same time, "atheism" is not an antonym for "religion": you can be an atheist and still be have any number of religious and/or mystical beliefs. Many Buddhists, for example, consider themselves atheists.
Once more: "atheist" only means that you wouldn't answer "yes" to the question "Do you believe in any gods?" "Theist" means you would. Neither one tells you more. If I said "I am a Stalinist" (I'm not), that would tell you something about the rest of my beliefs. If you say "I am a Fundamentalist Christian", that would tell me something about yours.
There are many people who don't know this or keep forgetting (or refuse to accept it), and automatically assume they know all about me simply because I lack the god gene. I guess the world is much simpler if everything is either entirely black or entirely white, but it makes things harder for those of us with wide-spectrum attributes.