user - Account verification: Only 1 account per person -

in community, every user should have 1 account.

so need solution verify specific account 1 user owns. time being, use email verification. don't need users' email adresses. try prevent multiple accounts per person.

but doesn't work, of course. people create temporary email addresses or own several addresses, anyway. register using different email addresses , more 1 account - not allowed.

so need better solution (easy circumvent) email verification. way, not want use openid, facebook connect etc.

the requirements:

• verification method must accessible users
• there should no costs user (at least 1$)
• the verification has safe (safer email approach)
• the user should not demanded expose private details
• ...

do have ideas approaches? thank in advance!

additional information:

my community browser game, namely soccer manager game. thing makes multiple accounts attractive users can trade players. if have 2 accounts, can buy weak players excessive prices no "real" buyer pay. "first account" gets huge amounts of money while "second account" becomes poor. don't have care: create account make first 1 richer.

very interesting question! basic problem here multi-part -

1. opening account trivial (because creating new email ids trivial).
2. but effect of opening account in game not trivial. opening new account gives sum of money buy players.
3. transferring money account trivial (by trading players).

combining 1 & 2, have problem new players have unfair advantage (which not have in real world). okay, drives new users site.

however adding 3 mix, have problem new players able transfer advantage old players. allows old users game system, ruining fun others.

the solution can removing either 1,2,3.

1. remove 1 - part focusing on. others have suggested, impossible 100% accuracy. there ways enough, depending on how stringent criterion "good enough" is. think best compromise ask user mobile phone numbers. it's effective , allows contact users in 1 more way. way make service "invite only" - assuring there defined "trail" of invites can uniquely identify users.

2. remove 2 - no 1 has suggested bit surprising. don't give new users bunch of money signing up! make them work it, similar raising seed capital in real world. soccer simulation have social aspects? how giving users money once "friend" count goes above number (increasing number of potential investors give them money)?

3. remove 3 - else has posted best solution this. adopt strategy new user has play 3 hours before allowed transfer players. or maybe add "training" stage game forces new player prove worth making enough money in simulated environment before allowed play real users.

or combination of above! combined heuristics matching ip addresses , looking suspicious transactions, possible make cheating on game unviable.

of course final thing need keep in mind is game. if goes lot of trouble gain little bit of advantage in simulation, deserve keep it. long having fun!