In many social sites, such as Facebook, Hi5, and countless others, upon signing up you’re encouraged to “add your friends.” 
As you use these sites, you get “friend requests” or “connection requests” to add more “friends.” Eventually, as you use these social tools, the concept of friend begins to blur. In fact, as the Inuit (we don’t call them Eskimos) were thought by popular culture to have 400 words for snow (it’s a myth), we’re approaching a place where we’ll soon actually need more words for friend.
I mentioned this at a conference, and I’m not sure I ever codified it properly. So, who is a friend?
According to Wikipedia, “Friendship is co-operative and supportive behavior between two or more people. In this sense, the term connotes a relationship which involves mutual knowledge, esteem, and affection and respect along with a degree of rendering service to friends in times of need or crisis.”
In Social Networks, a friend is someone who is willing to click “add this person” in a dialog box. We have very few ways of distinguishing other people’s true friends – the ones who share mutual affection or who would give service in a crisis – from their long time college acquaintances, neighborhood well wishers, elementary school reminiscences, and stalker ex-girlfriends. One early social network, Orkut from Google, actually allowed you to indicate how close you were to a person from “never met” to “best friend.” Today’s Facebook allows you to put friends into lists so you can ignore the ones you connected with but don’t really know, but that’s not the same thing.
The network that is most lacking in a way to distinguish levels of connection is LinkedIn. Since much of the intention behind the network is business networking and creating connections between friends, people often ask for referals to others. When you look for a way to make a connection to Bill, you may see that you’re connected by “John, Jane and 12 others.” Wouldn’t it be best if you were able to request the connection through John, who you know as well as 8 on a scale of 1-10 and who knows Bill as a 9 on the same scale? Instead you may ask Jane, who you also know as an 8, but who only knows Bill as a 2 – yet you may have no way of knowing this. This could lead to Jane awkwardly declining to make the connection, or having her request ignored.
I believe that as social networking services evolve, we’ll have more choices in how we distinguish our degrees of relationships, and how we expose that data to others. A project like the “Friend of a Friend Project” is doing so, and others such as Yahoo are attempting to start to use that data. Let’s hope we can somehow come up with words as descriptive as icy, powdery, slushy and packed to let us distinguish between our BFFs and our FOAFs.