Also, as a general rule of Internet forums, the larger the forum, the more idiots it attracts. That's why small, elitist forums with a more tight-knit community generally are nicer and more intelligent than, say, Gaia Online, a forum that by and large exceeds Something Awful and 4chan in terms of sheer size but also contains a staggering amount of idiots.
tl;dr If you don't want your precious internet forum to be overrun by idiots, keep it a secret.