Trying to get this ad shown to me, I though hey, go to some VSS question and it will appear!.
Much to my dismay, I've been reloading VSS Questions for the last half an hour without that ad ever showing.
That got me thinking: Why aren't you looking at the context of a question (tags, keywords in the title/body) to provide an ad? Wouldn't that make the ads more successful by being more relevant? May be there is a flaw with my reasoning that I'm not seeing (I'm far from an ad guy).
Keep in mind that I'm not proposing deterministic ads, that being ads that are shown only when certain tags/keywords appear, but rather a random statistical model that weights ads and gives a weight boost to the relevant ads.