As with anything I think it has its pros and cons. The pros - information is easier to access now than at any point in history. It is easier to learn, to connect with others in places outside of one's own backyard etc. Knowledge literally just a second away.
The cons - I believe texting and tweeting is ruining the ability of young people to write well and communicate effectively. I read things in advanced English classes written by college kids fresh out of high school and I cringe. It is barely understandable, loaded with spelling and grammar errors etc.
Cyber bullying would be another drawback. Kids carry cruelty over onto the internet and there have been several cases of kids pushed to suicide because of the non-stop barrage of abuse.