The OP should perhaps seek education before trying on the daddy pants. Your stupidity on this subject is made only more rich through your self-appointed authoritativeness.
Atheism refers to the lack of belief in gods. That is it. It says nothing of what is believed. It need not be based on science, facts, or logic. It is not mutually exclusive of religion (many religions are atheistic.
it can be split into two primary forms. Negative atheism is simply the lack of belief in gods. This includes what most people think agnosticism is. While these atheists are agnostic, this is not what the latter term means (clarification below). There is also positive atheism - the belief that there are no gods. This form can be agnostic (you simply believe that no gods exist) or gnostic (you know that no gods exist).
Atheism is not a belief system. This may rattle your self-appraised genius, santa-boy, but it is also not a proper noun and neither it nor "agnostic" should not be capitalized unless at the beginning of a sentence (on another grammatical note, definite is not that hard to spell). There is no such thing as a "true" atheist and those who suggest there is come off as far more ignorant than the Christian denominations that decry anyone they don't like as not being a true Christian.
As much sand as this may shovel into your vagina here, idiots who just want to make inflammatory posts attacking religion clumsily (not including valid attacks) are atheists. You have no authority (and no such authority exists) to shame them out of it on account of being an atheist. How stupid would it be for a non-Democrat to assume the position to dictate the behavior of all other non-Democrats? Then again, what do I know? I'm not as Scottish as the OP.
If junior would like to actually learn about issues before spouting off and brandishing ignorance, the Iron Chariots website is a decent (if skeletal) wiki that should point you to some very good sources.
And for those insisting that agnosticism is the position of "I don't know if gods exist" - you are wrong, though this may be a permissible ignorance. The word has been misused and bastardized since inception (never let a bulldog play wordsmith). While it does refer to claimed absence of knowledge, it has nothing inherently to do with gods. It doesn't say what one's position is, it merely describes that position. Saying "I'm an agnostic" is like saying "I'm inherently...". It must be accompanied by a position. One can be an agnostic theist, an agnostic negative atheist, or an agnostic positive atheist.
And before anyone goes quoting lay dictionaries, don't bother. They show common usage, not meaning. They will also tell you that "theory" means guess. It does in conversation, but not in a scientific context. The terms we're dealing with here are philosophical, not conversational. In this context, words carry more precise meaning.
