A couple things: 1) I ran an AdWords campaign on my own dime during the 2004 presidential elections and had a ton of fun geotargeting to the swing states. I must've pulled ~25,000 people to the site I'd built espousing my own viewpoints on election and am pretty sure I swung at least a few hundred voters to my way of thinking. Why individuals don't do this more is beyond me.
2) I've done the same for presidential elections *in other countries*. This too is one of the great things about PPC - you can easily run politic/social campaigns in other countries. Specifically, I've run campaigns a) appealing to moderates in Arab states; b) promoting a Syrian who's been exiled for her anti-Assad views; and c) showing the rest of the Arab world the true facts on Iranian censorship of its citizens.
SEM's ability to influence politics is almost entirely untapped at this point, but that will change.
