For quite sometime now, I have been successfully avoiding getting signed up for another one of several networking sites around. And I seldom use the sites i have registered to, exception being orkut (to keep touch with some indian friends, apparently its quite huge there) and linkedIn (for its professional touch).
But yesterday, I signed up for facebook, and to be true, its been good fun. Their methodology seems different and i am sure, i won't be cluttered with random people (like in myspace) who i have noting to do with. But at same time, it gives options to do networking with groups from colleges, work places, regional etc etc and also same time, its like a personalized homepage with personalized contents. And yesterday, they even released some sort of facebook platform which will allow anyone (individual, companies) to make content for personalization.
In short - its different. Give it a try and if you know me personally, see you there :))