https://steemit.com/steemit/@edicted/doing-the-math-on-reward-pool-abuse

So this math assumes that it takes 40 SP for +$0.01 upvote. Given this assumption, one can double their money on Steem in less than 2 years even though the Steem blockchain only has 10% inflation. (also assuming the price of steem is stagnant and not including compound interest)