As much as I enjoyed Friendster when it came out, it took quite some time to set up the various pictures and profile information, and then to go through to find whether my friends had previously joined, and if so add them or if not invite them, and then perform periodic maintenance as other friends joined but didn't know I was there to add me (or, to the more paranoiac part of me, did know and chose not to add me anyway). Much like having a blog makes me feel, it is nice to have a little web corner-of-the-world, where if people want, they can stop in and say a virtual, "Hi!"
But then, Orkut came out, and of course, some people liked that one better. Friends gradations is pretty cool; I always had the 7th grade question of "Are they really my friend? Or just my acquaintance? Or what?", and that solved it, while at the same time re-inforcing the 7th grade popularity contest in my head. (This friend is a better friend than this other friend, etc.) Orkut has its own profile system, which also serves to link people with similar social interests, regional interests, etc. It also takes a fair amount of time to fill out.
Now that I have the blogging bug, I'm discovering that the various journaling resources on the web are just another form of the social network software, though the focus tends to be on personal publishing. Sure, I can just publish my blog and never look any further, but Blogger also has a profile mechanism. Furthermore, my wife and several friends post on LiveJournal, and in order to see the more private posts, you have to be part of their friends. And there again, you have another social networking issue — where are your friends posting? do you have an account on their blogging system? do you have your profiile on that blogging system or can you point to some more generic profile?
The whole profile thing predates all of these services though. Even basic sales websites want to know your address and credit card information, but then go further to establish buying patterns and areas of interest to give you targetted advertising. Microsoft's Passport was a simple attempt to have a single roaming profile that other websites could use, so you wouldn't have to enter in all your information over and over.
It would seem to me that, with the proliferation of social networking products, that someone would undertake to create a system where people could publish their own profiles (with private information hidden) and that any number of web sites could extract the information they want. That furthermore, it would be extensible, such that if there's some new bit of trivia that a particular service to which you subscribe desires to know about you, you could extend your own profile with that information. There would have to be some kind of standardization, lest they ask you to produce the data in three different ways based on three different modes of consumption, but that seems like it would be relatively straightforward. In today's world of XML and XSLT transforms, you might even just be able to have the data once and just mirror it into other formats. Friends/Acquaintances would be referred to by the locations of their published profiles, etc.
In the interim, though, it seems an interesting exercise to see if I come up with the same Favorite Movies in the same order on the various web sites I have to fill in that information. Right now, you can clearly see that I'm of many minds about things (or at least am absent-minded sometimes).