I've always looked at the Internet with ambivalence. On one hand, I see the Internet as an amazing tool for research, outreach and entertainment. Nothing in the history of mankind has offered us such a comprehensive portal for communication and knowledge as the Internet. Before it, I found information exclusively through books like almanacs, encyclopedias, and the like. Once I got my first 56K modem, I was immersed in mining all of the hidden information and openness the Internet has to offer.
Soon though, it seemed that a sort of monopoly was occurring as social interaction migrated to sites like Facebook and website searches were filtered by Google. I started to feel that not only was it going to take more effort to surf the net "freely" but also that the Internet was becoming a more dominant force in my life. Checking emails several times a day, looking at photo albums of "friends" whom I hadn't contacted in years (or even gotten to know very well, for that matter). There was also the idea that my ability to concentrate was being affected. The speed with which I was able to browse different pages without much dedication surprised me and so I went hunting (i.e., googling) for some sort of answer to this mild paranoia. What I found was an online book called The Psychology of Cyberspace by John Suler (companion site).
The Psychology of Cyberspace (2004) is one of those sites that hearkens back to the "medieval" times of the Internet -- before Wikipedia -- when you'd find a highly informative page that was virtually all words; no pictures, no videos, no advertisements, just good old-fashioned "sharing". The sight is actually an online book that seeks to demystify the Internet and account for the effects of its presence. There are chapters on "Addiction to Computers and Cyberspace", "Personality Types in Cyberspace", "Hypotheses on Online Text Relationships", even "Online Gender Switching" and much, much more. A favorite chapter of mine is the "Online Disinhibition Effect" which deals with users' sense of anonymity and invisibility and even the notion that we create online personalities that may conflict with our "real" selves.
At this point, I think anyone who's been using the Internet for the last 5-10 years will have thought about at least some of the topics that are covered on the site. It's a very comprehensive study that may give us some insight into what the Internet might be doing to human psychology.