Originally posted by The Man
span, div, and s, at the very least.

what the hell do <!> and <mail> do?
I think the "i" can enable it so you can sorta hide text and it only shows up when the user quotes the text on the edit post screens, and "mail" allows posting of an email address as a hyperlink.

EDIT: Whats that tag that allows you to embed a sound or video file in your posts? I'm gonna add that one.