Theorem: Straight and simple. Internet is more addictive, more than drugs.
Proof: I have heard of people who go into rehab and consequently get out of drug addiciton. I never heard anything similar for the Internet.
Example Scenario: I have an hour to kill before the class. What do I do?
pre-Internet age: Shall go say Hi to this guy and probably go to cafe. Or shall workout. Or catch some sleep.
Internet age: Shall go change my Facebook/Orkut/MySpace/IM (read '/' as 'and') status. Report the same on twitter. Check mail every 2 minutes. Blog about the prized 5-minute conversation with someone.
Remedy: No Internet connection at home. Go for this mode where people can't access you that easily. No Internet, no mobile phone. This helps you realize what you are losing otherwise. :D