To "Pascal Monett":
It's not that simple, in-game ads are not browser ads, you need to find the right IP's and block those but a simple URL block in hosts won't work, and an additional problem is that they shove 'default' ads in via the company server that's needed to authenticate for online play, so when you block those IP's you can't play online or update the game.
And if you make some sort of utility that blocks them the 'anti-cheat' will detect something strange and might block your account.

Question about the article; are there other companies than intel and gamecompanies that use in-game ads yet? I generally stop playing games when they get in-game ads so I'm not on the up but last time I saw them ONLY intel and the gamemakers themselves made ads which makes the whole thing of profiling seem rather pointless since all gamers buy games and all computer users are targets for intel.

I'm sure that whatever game tries to push ads in the future will be countered by someone, somewhere, who will make something to block it.
And of no one does, well, the hosts file is just a few clicks away . . .

"I very much welcome any and every ad that comes my way! Especially those cool animated ones.".

*rubs his FF Flashblock plugin*

excerpt:
"The total online gamer population in the US went from 237 million to 305 million in the same time span. "

Uhm... There are only 305 million Americans (US) total, so that either means ALL Americans are gamers or you stuffed up your numbers. (Or Comscore has.)