I think there very few blatant multiple accounts on here (though one is quite amusing at times), I don't doubt there are perhaps some others that are only used very infrequently as I'd wager the mods shut them down quite easily if they become prolific as there are no doubt plenty of tell tale signs that trip up most people. I'm not sure the OP actually is a secondary account, he might be but he might also be one of these paranoid types who doesn't like leaving info online.
Looking at his posts he's decided to randomly edit some of them for no apparent reason (other than to remove all trace of himself) - he's been a member since 2002 and posted very infrequently so may just be a lurker.