There are forums and clubs and groups of friends who gather, both online and in person, to discuss this art form. Generally, I steer clear of the topics related to pure mentalism, because that's not my specialty, and because I often find myself getting pissed off when I read about it (such as the time I saw Uri Geller on the cover of a magicians' trade journal). But this evening, I broke down and peeked at the mentalists board on a forum, and found a topic in which people were discussing Sylvia Browne (if you're unfamiliar with Sylvia Browne, I suggest you visit www.stopsylvia.com for more information--that site, maintained by Robert Lancaster, has an amazing wealth of information). Anyway, the point is, I was prompted to post a discussion of ethics for mentalists and magicians, because apparently, common human decency are in shorter supply in my profession than I had thought.
I'll begin by trying to explain the difference between magicians and mentalists. A magician uses trickery, sleight of hand, psychology, and various other means of deception to accomplish the apparently impossible. Mentalists do exactly the same thing, but they specialize in apparently "mental" or "psychic" feats. Basically, mentalists are magicians whose effects are apparently accomplished with mental powers.
Sylvia Browne and Uri Geller, were they legitimate entertainers, would fall into the category of mentalists. Their apparently psychic feats seem to happen by mental power alone. But of course, they aren't really doing these things--it's all trickery.
So, back to the forum topic. A guy mentioned Browne, and here are some samples of comments posted to the forums.