How difficult it is, really, to say anything truly original about Facebook. No one really expected it to take over our internet lives the way it has; no one really understand why, out of all the social networking sites, it emerged as dominant; no one can really predict what is going to become of it, whether it will die by the wayside like so many other internet phenomena, or whether it will become an internet-within-the-internet: a safe sandbox in the wild wild west of all the rest of the internet, with its fictitious personae, its masquerading identities, its child molesters, its identity thieves, its hackers with malicious code ready to jump into your computer and turn your life upside down. And, as icing on the cake, it has Scrabulous.
What makes Facebook different is that people are, generally, who they say they are. It's easy to spot a charlatan because he or she will be lacking in friends who vouch for this person's identity; even a group who conspire to create a fictitious persona will eventually run out of numbers. And if the conspiracy grows too large; then, well, it isn't much of a conspiracy, is it? Identity on Facebook has one foot planted in 'real', i.e., non-online life; you meet someone, and then keep in touch via Facebook; you find an old classmate, and then meet up in person. Anthropologists and historians from the future who are researching the current period in wester civilisation will suffer not from paucity, but from plethora, of information. All of everyday life is archived on public and private servers, somewhere, from personal websites to darker side of humanity, in chatrooms where individuals with names such as alz36697_tg trade pictures of children or information on which public urinals are the sites of anonymous sexual activity. Facebook is, literally, the face of the internet, as opposed to its groin. It's a happy, shiny, beaming face, where all acquaintances are friends, messages are polite, and everyone gives cutesy virtual gifts and plays little games and quizzes.
It's also wonderful for studying the dynamics of social networks, as a social networking site is likely to be. Like Google's ranking system, the processing of finding and making friends operates on the basis of eigenvector centrality. It isn't so much how many friends you have, but how important your friends are. So you can be very outgoing, but your five hundred friends who have less than a hundred friends will not matter as much as the few dozen friends you have who are immensely popular. Inbound popularity (people like you and want to be friends with you) counts differently than outbound gregariousness (wanting to be friends with everyone). These people are like the Van der Luydens in Edith Wharton's The Age of Innocence, whose scarcity makes them sought after, and whose friendship becomes a societal badge of approval. Not, of course, that I'm doing anything like counting the number of friends that I have.
The feature that I love most about Facebook is the newsfeed. For someone who has moved around a lot and left groups of friends in various cities, some as near as Oxford, some on the other side of the world, receiving a terse report that so-and-so is getting married, has broken up, has just had sex (isn't that what 'has changed from "single" to "it's complicated"' means?), etc., makes me feel connected and still part of their lives; even as, at the same time, it can drive home the reality that one is very far away.