The more popular one of these social aggregation websites becomes, the more likely there will be these types of users. Reddit, which was once a safe-haven, recently ousted one of its own users as an SEO spammer, and they were not kind to her once they found out. Here's the thing though, she spammed sites that she was hired to promote, yes, but she also contributed to the community with advice and stories of her own interest. Upon closer examination, her personality was not all that likable and her ego was the size of Everest, making it easy to antagonize her, but if she were more humble and apologetic about it, I don't think the community would've been as harsh toward her.
Which is the problem I have with these social aggregation websites: that not every user has an even say because some users are getting paid to vote the way they do. And now you've got another corrupt democracy advertising itself as if it's something it's not (much like real democracy?). On a social study level, it's interesting to see these problems arise, and I love to see what can be done about it. I know MetaFilter has a $5 fee for its new users, but I doubt that will filter these social spammers entirely. Not to mention there's no democratic voting on MetaFilter, it's just a bunch of news stories put together, it's more like just a regular forum.
Some users aren't paid in money, but with a reciprocated vote. So you've got User A upvoting User B's submission to the community in exchange for User B to upvote User A's submission. And these users form their own little gang, upvoting each other's stories to the top of the social aggregation community. So the story you see at the top didn't get there because people liked it, but because User A just upvoted so many submissions in exchange for return votes, that that's where his upvoting got him, to your front page.
And then there's Netflix, which had the problem that users could upvote their own submissions an infinite amount of times, eventually catapulting themselves to the front page of every review page. And now the Netflix member reviews you see aren't actually the best reviews, it's just been upvoted by a user with his own mouse and a lot of spare time. Take a look and you'll see the same usernames next to most of the reviews at the top of most Netflix pages. It's irritating once I saw it. These users have built their empires of dirt at my expense-- I'm not reading a review that really was as helpful as it was voted on, I'm reading the same person's opinion for different movies, he's made himself his own popular critic.
All I ask for is popular social aggregation website minus the paid voters, that's pretty much the TL;DR of this entry. I should probably spend my rage on more worthy things, but this one really gets to me.