Agnostics say "don't know" whereas atheists say "I know/believe that there is No god". The athiest has no proof of his position, he takes it on faith.
There is a subtle difference between agnostic and atheist.
Some atheists are rabid about it and want every trace of religious expression supressed in the public arena. They force their "no god" on everyone else.
Some rabid atheists, like Madilyn Murray O'Hare even formalize their atheism into an institutional religion.
No they don't. The very word "atheist" is like "aleprechuanist" - without a belief in (god/leprechauns). There is no separate concept for "not knowing" whether or not there are leprechauns, either one accepts the existence of leprechauns or you don't. Similarly if one "doesn't know" or "doesn't care" if god exists, then you are an atheist, you are without a god.
You mean O'Hare in a drum?