I have what may be the world's simplest solution to multiple accounts. Have everyone (optionally) register their e-mail for account recovery purposes. No one should need more than one account unless they are hiding something or causing trouble. To ensure that several accounts are not registered to the same person, track IPs for which accounts are registered to which address. Any IP address with more than three accounts registered to it could be red-flagged by a bot to be investigated by a senior member, who could then take appropriate actions or issue warnings. I know that Wikipedia already tracks IP for unregistered users, and registered users (if they have good intentions) should not mind it being recorded by a bot (which would keep these IPs secret unless it flags them, as above). I'm sure that such a system would also help to get rid of wackos, cranks, and hooligans, as such people often get banned and just make umpteen different accounts so they can continue to be offensive. For users forgetting their login, have them put in their email address and a couple of preset answers to questions selected at the time of account creation (or later, via a userpage option or something) ex. (your date of birth, your mother's maiden name, your middle name, the color of your first car, etc.). They could then be sent the information in a bot-generated email. I've seen similar systems on many other websites.