My friend Owen has written a very helpful post about blogging that glorifies God. It could just as easily apply to Facebook, Myspace, or any other social network. Read it here. Here are his five points:

1. Be careful about narcissism. (I have written similar concerns here)
2. Make your blog about ideas.
3. Watch out that you're not contributing to a culture of amateurs.
4. Remember that blogs aren't really that significant.
5. Seek accountability in your blogging, like anything else.

"Ordinary people can also find a taste of fame on the Internet. Anyone can put up a Web page, start a LiveJournal (LJ) [or facebook or blogger], or post to message boards. Blogs are built around the idea that everyone wants to hear your thoughts [narcissism]. Had a bad day? Tell the world about it on LJ. Proud of your athletic ability, your family, your hobbies, your witty writing? Create your own Web page."
(Dr. Jean Twenge in "Generation Me" p. 89)