Here's what I wrote on the topic three years ago:

"Some notes on how to make the internet more like a book, magazine, or phone than a television. That is, more like a tool than a world:

1. Do not use iGoogle, FriendFeed or any other service that provides you with "status updates" from a number of services at once. This leads to a condition where "checking your email" becomes "checking everything". Every hour you will find new interesting things that will bifurcate your attention into many worlds. (However, I have the feeling that an iPhone/iPod Touch, which is in a sense a portable iGoogle, would be a positive replacement. Better to check constantly on a non-immersive device...?) [My new opinion on this is that menu-bar style apps allow you to check email/Facebook etc. more frequently, but faster, which can break the habit of checking your email every 5 minutes and performing a full context switch.]

2. Do not invest yourself in social networks like Facebook. Don't join groups that encourage participation or frequently send out mass-messages. Don't friend anybody that you don't really want to read about. Use your profile as nothing more than a node (don't post anything to your profile that you might someday want to fiddle with). See it as a communication tool: glorified email/chat. Rather than making certain parts of your profile private, make everything public and make sure that anything anybody can see is something that anybody can see. (This means that you must occasionally un-tag photos and delete Wall posts.) Don't add any applications. Don't try to model your real-world social life.

3. Twitter is cool. It's addictive, but it doesn't take any time. <5 min. to check what your friends have written and update.

4. Blogs are cool. As long as you're producing content, there's nothing to feel guilty about. The point is not to stop doing drugs altogether, it's to make sure that every time you do drugs, you're using them to enhance your creativity and your relationships.

5. Use Times for aggregating feeds. Nothing compares. It frees you from the feeling that you have to read every article. Promotes quick scanning, just like a newspaper.

6. There's nothing to be done about email. It's addictive and time consuming and it's not going away. Make sure that you're not on any corporate mailing lists (Apple.com, stores you've bought stuff from). Filter mailing lists into folders. Practice self-discipline. Don't see yourself as somebody who 'replies within an hour'.

7. Create a habit of taking notes when you go on a tangent. This will force you to think deeply and remember what you've learned (plus you'll have it stored for future reference). It will also force you to slow down. I use an Instiki wiki running on my server so that I can access it from anywhere (though I'm considering switching back to desktop tools like VoodooPad and DevonThink).

8. Favor anti-design. Anytime you have any control over CSS, choose a white background with black text and blue links. Or find some other theme and stick to it. Remember, the internet is blue.

9. When you can, use UNIX (command line). It feels more like a tool for doing tasks than a world.

10. Make sure that Facebook sends only two types of notification to you: notification for Messages and Wall posts. This way checking your email means checking your email and also checking the only time-sensitive feature of Facebook at the same time, thus allowing you to ignore Facebook."