[joeykrug]

Sybil attacks are addressed due to the way reputation works. Reports are a weighted average - so the more reputation you have, the more your votes are weighted. You could make a billion separate accounts and send them each one reputation, but there's no discernible difference than if you had just reported with one account with one billion reputation.

[joeykrug]

but you can't make more reputation out of thin air by creating new accounts/addresses, just as you can't create Bitcoin by making new addresses