It doesn't seem like five years since Facebook appeared on the scene. I was slow to join the throng--my friends list numbers only 242 of the 110 million people who have joined the site since its inception.
Facebook is less juvenile in look-and-feel than MySpace, which it has overtaken in popularity. It is also a lot cleaner, again in look-and-feel but also in content. It also lacks the sexual content that plagues MySpace.
Facebook is more generalist in approach than some other social networking sites, such as Linked-In, which seem aimed at people looking for jobs and customers instead of communicating with people they already know. If you want to exploit your friends, Linked-In seems an excellent place to do it. And they'll exploit you in return.
Practical Social Networking
While I am not wild about social networking sites generally, as they can easily become colossal sinkholes for time, I've come to like Facebook a great deal and even consider it an important business tool.
Whole books have been written about promoting your company and its products on social networking sites. I won't wade into that swamp, though I think you have to be very creative to succeed. I also wonder how possible it is to niche market on Facebook the way search-oriented advertising can target an audience on Google.
To me, Facebook is a less personal medium than instant messaging, but more personal than email. I keep two or three IM clients continually open on my desktop. They are how family, closest friends, and a few business contacts reach me. I use a limited amount of SMS for the same purpose.
I don't keep Facebook open all the time. I check-in maybe a few times a day, but have sometimes gone away for days. I receive occasional email alerts and have the Facebook client on my iPhone, just in case I need it while mobile.
My main purpose for Facebook is keeping up with what a more distant set of friends is doing. These are people with whom I share common interests and like to know what they are doing.
You don't get on someone's friend list without their permission, so people are willing to share information they wouldn't post in a truly public space. Posting on Facebook also means you don't have to say the same thing to a bunch of different people just to get the word around.