I say "hack" in the most favorable light. It's a clever idea and theoretically beneficial.
I noticed that an old question of mine suddenly started getting a lot of renewed attention. The question had been answered, with an answer accepted. But another user added a well reasoned and insightful answer to the list. He also opened a +100 bounty on that question.
The resulting increased attention quickly got his answer quite a lot of up-votes. Well more than the 100 points he had spent on the bounty. Therefore, he gets a net rep profit out of the transaction.
So here's the hack:
- Find an interesting question
- Research and provide a very good answer
- Open up a bounty on that question to attract attention and votes to your new answer
2 and 3 may be out of order--I didn't see the timing of it. But either way, assuming he gets more than 10 votes, he still gets increased rep out of the deal.
I don't think this is necessarily bad for SO - it does generate some useful discussion and insightful answers. Plus you can increase your own rep very rapidly by making your answers highly visible, and therefore frequently voted upon.
However, it does slightly change the meaning and purpose of bounties away from starting a discussion and toward self-promotion. Still, interesting.