I copy and pasted the second part from the steemit.com FAQs. ;) they continue:
If your post or comment that was downvoted still received more upvotes than downvotes (weighted by SP), then the net effect on your reputation score will still be positive.
on the other hand, you never know when someone with a lower score has a huge wallet and vote you are missing out on.
Yup yup... imagine being in the first 1 million user group of Facebook which today has somewhere near 1 Billion users. Maybe Steemit doesn't fare anywhere near as good as Facepuke but even it comes up 75% shy of Reddit.com that is still some 75-100 Million users putting most of us in elite category here on Steemit.
Steemit has two barriers one is getting people to sign up and the other is retention, right now those are serious issues. The question is, when will Steemit.com stop being beta?