I saw one guy just replying to comment after comment by himself, giving each comment a $25 upvote. The thread was about 100 comments deep when I last checked. So I don't know if limiting posts is going to help a great deal.
Not to mention, if we want people using apps like Steepshot the same way they'd use Instagram, then you want them to have the freedom to post 1000 selfies a day (for better or worse lol)