It really revolves around good parenting. Doesn't matter what it is: TV, radio, talking or texting on the cell phone, internet, video games, even books - if you don't parent the child and limit their use, the usual problems will arise.
My sis put my foot down with my nephew around 5th or 6th grade and made him do non-online, real world things because he was getting so addicted to video games. Now he's a freshman in college with varied interests both online and in physical reality.