Some kids just grow up around computer games and video games than with friends. I mostly blame parents for this because that's part of the socializing stage in a child, but in other cases, people just get that obsession with games. A lot of people feel more "confident" talking to people on their computer games than in real life too.
Because it's more fun sometimes? lol. You have control over a character. Outside games sometimes just doesn't do it. However it's the parent's job to limit the amount that children spend in front of the computer and tv, because too much is really bad for their development.
Another big part of it is just that technology has evolved to the point where it's easier to just do things online whether you are a kid or adult. That's why there is so much online shopping and video game playing these days.
Friends do contribute a lot for these habits of kids isn't it? but as you said, even the parents should take the blame as without parents controlling, children are bound to get addicted to such sort
just like with candy and junk food:) lol.