Yesterday I wrote an article on the movie Billy Elliot, saying that in one shot you can see my university. The result is that Google's ads offered self defence classes and home security. Adwords are a clever idea; I certainly prefer targeted advertising, even the religious junk, than ads for debt reduction, casinos and the rest that I get on other sites, but on this evidence they need to be a bit more sophisticated.
Google: if you are reading this, you need to scan for words in context, not just words.