First Monday has published an excellent paper, Friends, Friendsters, and Top 8: Writing community into being on social network sites, by danah boyd, about sites like MySpace where the information you display about yourself includes a list of who your "friends" are.

From the paper's abstract:

"Are you my friend? Yes or no?" This question, while fundamentally odd, is a key component of social network sites. Participants must select who on the system they deem to be 'Friends.' Their choice is publicly displayed for all to see and becomes the backbone for networked participation. . .

I always find danah's writings on the social network sites very illuminating, and this paper helped me connect the dots between many of the issues she's been writing about over the past couple years.

Actually, I think it's because of something danah wrote several years ago that I've been a bit more cautious about whether I refer to people I know online as "friends" or "colleagues" or "acquaintances" or "online friends"—I haven't quite figured out consistent terms to convey (e.g., to my family) the different nuances of how I hang out with people offline / online. In conversation, I try to reserve the word "friend" for people whom I do (or, plan to do) fun things with in person.

So, by that definition, for example, I'd probably call danah a friend (playing werewolf is fun!). But, I've only hung out with danah in the context of professional conferences, so maybe "colleague" would better convey the connection?

Anyway, when, on social network sites, you display who your "friends" are, there's an interesting overlap, an interesting conflict and an interesting divergence from who your friends are offline. And, danah's paper really illuminates the dynamics of these overlaps / conflicts / divergences.