Nervous about what your kid might come across on the Internet (cyberbullies! nudity! creepy people!)? Feel like all that time online is, well, a waste of time? You've got a lot of parental company. But surprisingly -- and hearteningly -- a new study from the University of California, Berkeley, and the University of Southern California shows there's less to stress about than you may think. The researchers spent more than 5,000 hours observing kids on sites such as Facebook and YouTube and found that Internet use improved communication skills and mental sharpness. "Even though it seems like goofing off to parents, there's actually a lot of learning taking place online," says lead study author Mizuko Ito, Ph.D. "Kids are picking up skills on how to search, socialize with others, and successfully navigate all the emerging technology out there." Plus, that kind of self-directed learning is different from what most children get in school, where the teacher is the expert and there's a fixed set of content to master. Of course, this doesn't mean it's okay for your child to spend every free waking second in front of her computer screen. We like the American Academy of Pediatrics's take on moderation: Limit online time to less than two hours a day.