In an interview with Foreign Policy, Eric Smit (then CEO of Google) had an interesting answer when asked if there is a downside to hyper-information access?
I am worried about the decline of what I call deep reading. In other words, the sort of "here I am on the airplane, there's no Internet connection, I am reading a book thoroughly" reading. You do less of that in a world where everything is a snippet, everything is an instant message, everything is an alert.
If you're worried about what the Internet is doing to your brain, read Nicolas Carr's book: The Shallows: What the Internet Is Doing to Our Brains.