There are two very long threads in the search forums talking about how Google's AdSense ads are showing political ads on their sites. A WebmasterWorld thread and a Google Help Forum thread has discussion on why these ads are showing up.
In summary, there are thousands of publishers out there that put Google AdSense ads on their sites. Typically, the ads shown are relevant to the content of their site. But with all the politics taking place and today being election day, the ad dollars are going towards getting voters out to vote for their agenda.
The problem with this is that many publishers are not interested in supporting one candidate or proposition over another. They don't want their content or site to be discussing the hotly debated topic of politics, especially at this time. But at the same time, it is almost impossible for them to shut these ads off - without taking down the ads completely, which is costly. The publishers just want a way to turn off political ads.
The same thing actually happened to me yesterday. When I announced the Election Day theme here at the Search Engine Roundtable, people commented that my ads might convey that I am voting for McCain over Obama or I might be voting for a certain proposition over another.
If you take a look at the contextual ads on my blog, you will notice that my request for people to vote, has sparked ads for McCain. Here are two sample ads, one from Microsoft ContentAds and one from Google AdSense:
Some publishers have taken the extreme of losing two days of online advertising income due to not wanting to have their site support A over B.
Should Google and other contextual ad programs offer publishers a way to opt out of political ads?