At that age, the single most important thing for a parent is communication with that person, and if necessary, intervention. It's the age where you start facing more adult issues, and teenagers should be allowed to try and work through them, but if they get bad it's time to step in. Many parents don't currently understand the 'world of technology,' it's a foreign issue to them, not one they understand... or care about at all in some cases. You see it more than you would hope.
I think the failure to understand is the most prevalent issue right now, because the current generation is the first generation where gaming is not only commonplace, but accepted. It's breaking out of cult/niche status. Teenagers having their own computers is becoming far, far more common than it used to be. Gaming itself is not a problem, computers themselves are not a problem. A lot of parents and teachers like to either place blame on the objects themselves (my grandparents, who helped raise me quite a bit, did that for a time), or ignore it entirely. Understanding and communication is the answer, not laying blame, not ignoring the situation.
Gaming should be a hobby, and while you can make really good friends while gaming, I don't think it should be a 'second life.' This is coming from a guy that ended up living with people he met on WoW, mind. I know firsthand how good 'internet friends' can be. There's a balance you have to find though, and when it comes to younger people, finding that balance can be really, really hard. It's not something you can always do alone. Parents (or other mentor figures) really need to have a role in finding that balance, even if it needs to be done with a little force.