Last week the gaming news sites were discussing the revelation that Sony had inserted advertising post-launch in its futuristic-themed racing game WipEout HD. The biggest furor over this was the fact that the advertising was not present when the game initially came out (it was delivered via a patch after launch) and it was extremely invasive in context: it wasn't simple billboards along the track but video commercials played during the loading screens which, in many cases, artificially increased the length of time a user was waiting for a track to begin.
Having previously worked at Yahoo! doing internet banner advertising, I do fear the future creeping encroachment of advertising as companies seek increasingly to monetize every possible facet of everything. Games are the last place I want to be forced to see commercials.
Part of why Sony's move was so offensive was because it was not there when gamers bought the product, only appearing later. As the Ars Technica article rightly points out, there's not much a customer can do other than complain once that happens. The ubiquitous GameStop ads peppering every possible skyscraper in Prototype's virtual Manhattan were annoying, but at least I knew it was present when I bought the game. Anarchy Online also toyed around with in-game advertising, but this was only for players using the free version of the MMOG. In that context, or if Sony's move had been for multiplayer only (those gaming servers don't pay for themselves!) this would have probably not raised so much flack. But forcing players who have paid for your product to be subjected to unwanted advertising that in many cases holds them hostage to a loading screen for twice as long as they needed to be is sure to only inspire vociferous hatred towards you and your company.
Sadly, though, this sort of thing is likely to only become more and more common as gaming shakes off the taboos and stereotypes of being the hobby of only mouth-breaking, unemployed nerds living with the parents. There is a lot of money to be made for contextual advertising inside videogames– not just the MMOGs, but the single player console software too. Sony did the right thing in pulling the ads from their game, but it's all but a guarantee that they're going to be back in some other context. And it's extremely likely that more game development companies are going to follow, whether gamers want them to or not.