I wouldn't mind in game ads if they put them on billboards and maybe in-game TV commercials?

I never thought about it before, but if done properly, it could work. Although I see it more like some kind of easter eggs, so they should be rather recognizable brands, like Coca-Cola commercial, but in TS style and in Simlish.

IKEA and H&M are also good examples of not so intrusive ads.