Questionable agents, who unlike reputable agents are unable to impress potential clients with their track records, sometimes try to project an aura of professional competence by attaching lots of (apparently) professional memberships to their names.
Mensaguy, whom I discussed a few posts back (his agency is a front for an expensive editing scheme), uses this technique. His letterhead prominently lists a business organization, a couple of Who's Who tomes, and, of course, Mensa. It's a good-sized list, and it might actually look impressive if you didn't realize that none of the memberships are relevant for a literary agent.
So what professional memberships are relevant?

