Glenn, Not wihthstanding a Wall Street Journal pooh-poohing Twitter and to a lesser degree Facebook, FB can be a reasonable idea.
A regular FB page (a friend Page) is one usually for your personal friends.
A fan page is one for "Fans" who want to keep up with your business side. If you notice there is a huge amount of busineses and universities that have Fan pages. It is a way to get out their message in a less formal way (web site). It is also a way to tap into a different demographic than what you normally have. People do not look at your web page every day to see what is new. That is FB's Fan page use.
The fan page is not a place to detail your latest drunken tryst - save that for your regular FB page. Many people mix their personal and professional on their FB personal page. This potentially mixes messages and also dilutes the reason to read the personal page.
To further screw up your handle on FB, many businesses started FB "Friend" pages several years ago. Fan pages are only about about 1 1/2 years old on FB. Fan pages were specifically set up for businesses by FB.
If you have a blog, a lot of people tie their blog into their FB page or Fan Page. All of this underlines the point, how much time spent on FaceBook/Twitter/MySpace is useful and how much is useless time blown that could have been spent on working on a new artwork or playing with the kids?
Hopefully this will help you understand my take of the truth behind the FB hype.