As a recent salvia user, I've looked all over the web seeking research on it (including erowid of course). Right now there seem to be no long-term physiological or psychological effects that we know of, but research has been minimal. Just remember, moderation in all things. Overindulgence in any hallucinogen is bound to have negative psychological effects. Stick to low-moderate doses, and don't do it every time you get bored.

As for the drug-posting rule, I was under the impression it only regards illegal substances, so I don't think it should be a problem.