I'd like to know too, just out of curiosity, but I think that all platforms have this problem. I understand that there's a fairly large industry for facebook and twitter "click farms."
OTOH, the point of stake-weighted voting on steemit is that in a practical sense it shouldn't matter. If you split your stake among 100 accounts or 1 account, your overall influence is the same. Regardless of how many accounts they use, people who invest more (in the form of time, money, creativity, etc...) have more influence than people who invest less.