The ESRB is the self-regulatory industry group that's responsible for passing out game ratings to game developers, and marking whether games are appropriate or inappropriate for younger gamers. So far, they've been pretty hands off on the App Store, relying instead on iTunes' Application Ratings to let consumers determine what's right for them. However, gaming on the App Store is getting bigger, and the ESRB has already shown interest in looking at App Store apps.
Personally, I don't think this is needed; the App Store environment is already held down with an iron grip by Apple's editors, and if anything, it's probably too sensitive. Besides, as a former GameStop manager, I can confirm that the ESRB's ratings had little to no effect on most purchasing decisions in my store. Any parent who's responsible enough to monitor their child's game playing can probably already tell, even without an explicit rating, what's appropriate and what isn't.
On the flip side of the argument , though, it could be said that if Apple wants to be one of the big boys in gaming, it should play by the big rules. What do you all think?