Having said that, there are probably a similar number of websites that negatively impact us. I recently deleted my personal Facebook as I'm tired of reading meaningless status updates from someone I spoke to 4 times in high school. Not to mention scrolling through the news feed was a constant distraction.
I've recently committed to only reading and listening to information that is informative and valuable. Below are few sites and blogs I enjoy:
Smart: TED.com, coexist.com, google.com/talks
Soccer: prosoccertalk.nbcsports.com, espnfc.com, guardian.com/football, theoriginalwinger.com
While I feel the internet can be an excellent learning vehicle, we must be careful. The social aspect can be quite dangerous (as I've experienced) by diverting attention for long periods of time.