Everyone uses the web quite differently, but I've noticed some strong usage patterns among social network, tagging, and blogging users that I think hold true.
The first type avoids social media altogether. It scares them. They say things like, "I don't want to expose my whole life on the web." They can't be found on Google and actively attempt to clean up their digital tracks. These people are to be avoided at all costs. Clearly they either a) have something to hide, like a body in the trunk of their car, b) have serious impulse control issues and if given a Flickr account or blog will immediately start posting pictures of their genitalia, or c) suffer from Usenet related alcoholism, because its all to easy to do a shot everytime someone responds to an annoying thread with "unsubscribe" in the body.
The second kind is a closet social media user. They've secretly had a LiveJournal since the first time they heard Ani DiFranco. (Mood: Angsty) They break into a cold sweat anytime they read stories about people fired from blogging, but secretly, they're hoping to be found...to be led to freedom by an LJ revolt where everyone goes to the window, opens it, sticks they're head out and yells, "I have an angsty LiveJournal blog, and I'm not going to keep it private anymore."
Of course, it never occurred to them that they use the same screename on their AdultFriendFinder profile.
The third kind of social media user is the happy medium most social users hope to achieve. They don't know how many RSS subscribers they have to their Tumblog-- and its mostly people they know anyway. They read Perez Hilton just as often, if not more, than TechCrunch and edited Wikipedia just once--to erase one benign sentence just to see if it would work. They like the idea of Twitter, but they only know 2 people who use it and fail to see the value of following Scoble or Calcanis, because they've never met either of them.
The fourth kind of social media user uses social networks to reflect and leverage their real life with worldclass efficiency. When their cable goes out, they LinkedIn their way to the night shift operations manager at Cablevision, who also happens to share the same music tastes (Wow, you like Radiohead, too!)... Cable back on in 4 minutes. Everything gets delivered, and expenses get tracked by both their social expense tracking community and Najesh, the Skype enabled personal assistant from Mumbai. Never alone, this user is always a Twitter or Dopplr notification from meeting up with someone they know, even snorkling in Fiji.
The last kind of social media maintains social media as their one and only form of social. "What do you mean offline?" They live in places with the lowest population density to downstream rate ratio in the country--not another man made structure for 22 miles, but they've got fiber to the home. All of their profile photos have that grainy blue glow of a webcam shot and they don't get it when people decline their friend invites because they're not friends. "Yeah...duh... that's why you click accept... to become friends!"
Any of these too close to home?