I've seen quite a bunch of "popular" votes recently which just rephrase a bit the next popular answer but suddenly get a bunch of votes.
I assume this may be down to people using their social network to vote on their responses and I feel this is tweaking a bit the vote system as original posters do not get the recognition that the points system should support.
There is an incentive for users to use their social network, of course, as they receive points. However, seeing this happened a few times I feel less motivated myself to answer in the future.
How will stackoverflow balance against these techniques?