o3o depicts the o's as eyes (like o_o), and the '3' as a puckered up mouth.

An emoticon often used by weeaboos, faggots, and 13 year old boys.

Despite the common use of emoticons, this one in particular, is almost always used after every word, pause or sentence. In some cases, even before a sentence.

Seeing this in a chat log or forum post can often cause heart attacks, strokes, seizures and in rare cases Anaphylactic shock.