So far, I have heard of things like Manhunt2 bieng given an AO, that RPG being given an M because of a mod, and I have to ask, what can the ESRB do for me?

I see it like this: They play it, and they rate it. Now, I understand some stores don't sell games if they don't carry an ESRB rating, but this raises my ultimate question: Doesn't the ESRB just limit you? If you have an ambitious title, and they give it an M, that means that nobody under 17 can buy it, which is a relatively large group. Also, if they give it an AO, almost no stores will sell it.

So I just have to ask, what are the good things about the ESRB?