@bitcoinflood, i would think that a system like that is quite hard to implement. but then again, the whales with a lot of steem power wouldn't upvote the spammers, being self aware that upvoting them would only benefit them. therefore, they only upvote the most meaningful comments. that being said, there becomes a time when a blogger has a lot of followers, and they become aware of just how much meaningless spam they receive.