1. You are busy enough with actual work. When not working, while at work, you have enough to do with email, myspace, facebook, linkedin, youtube, blogging, and porn.
2. You enjoy real interaction with real people- The old fashioned way, in chatrooms and forums (or in person)
3. You signed up for twitter to see what all the hooplah was about, and just didnt get it
4. You were one of the first people on myspace, and everyone made fun of you. And now you are the only one over 30 on myspace, and people think you are a creepy weirdo. So now you shun new social media technology
5. You joined twitter and no one wanted to follow your tweets and they were really friggin good.