The world of “social software” sites is, for some unexplained reason, hot right now. I don't quite understand the allure, frankly; maybe it's because I'm a loner whacko or something, but I find the sites like Friendster and Tribe.net to be a bit like college bars–filled with cliques and guys on the make.
That's not to say I avoid them completely. I have accounts on both Friendster and Tribe (and I'm a little miffed that I didn't get invited to join Orkut; there's something about an invitation-only”0social network” that's, well, antisocial ).
I've used Tribe more regularly than Friendster (which from my experience is as slow as molasses). Tribe is in some ways similar to craigslist, which started basically as a job-posting service but has turned into what I call “community-ware”–a place where people can trade information, find services, and generally do a lot of the things they used to do on Usenet before the bozo and spam level choked off any remaining usefulness.
But I digress. Tribe.net has features like event planning, classifieds (which you can filter based on how close your relationship to the poster is), discussion boards with their own URLs (which I've set up a few of), and a number of other interactive features that go beyond just trying to score a date.
To tell the truth, the killer feature that Tribe, Friendster and Orkut all lack is what LiveJournal has–permission-based sharing of stories.
LiveJournal is, on the surface, yet another blog hosting site. But it has one feature that other blogs don't–you can designate people as “friends”, and set the level of privacy on entries to allow only them to read them and/or post comments. You can also look on a page tied to your journal and see all the recent postings by your friends, and set up community journals.
My wife has a LiveJournal, and she finally succeeded in getting me to sign up for one. LiveJournal doesn't have the social networking aspect of “social software”, in that it doesn't automatically reveal to you who friends of your friends are. But it does have the effect of building tight communities of people quickly because it allows them to share things over the web with relative privacy–something that Tribe and Friendster don't have, really. I mean, sure, Tribe and Friendster restrict access to your identity info to a limited network of people (four degrees of separation for Tribe). But with 6 official “friends” on Tribe, I have a network of over 21,000 people who can read my details; and I can't mix friends-only and public commentary in a “tribe” discussion board.
So I finally succumbed and set up my own Livejournal account because of the privacy controls–I can write something there with certainty of who will be able to see it, and others can post knowing that I can read what they post (if they let me) without causing problems with work or family. If there were some way to combine some of the features of Tribe with the journaling capabilities of LiveJournal, well…that would be social software I could give a testimonial for…