This is disconcerting. I started reading with the assumption that HTML5 has nothing to do with it and it's another case of people confusing the nature of the tool with its usage, but — that's bad craftsmanship from browsers. I wouldn't want to live in a glass house, even if I could do inside of it however I please.
I wonder what's the extent of the problem. Ad networks are known to be parasites upon unsuspecting people, but I've never encountered this bad of an issue. Then again, I rarely go out looking at ads' code.
Web developers have nothing to worry from the news. It's the casual web user that's under threat of forced surveillance.