The downside of Facebook is that its relatively static; because I only have a few friends "in real life" (IRL), it's not updated very frequently. FriendFeed, on the other hand, is updated constantly with news, banter, photos, and so forth.
To use a poor analogy, FriendFeed is like a coffee shop that I can visit several times a day to meet and greet my online friends; Facebook is more like church, where I can see my (extended) friends and family every Sunday morning.
To use that same analogy, it's not an either/or situation: I'm not going to stop visiting coffee shops because I go to church, nor will I stop attending church because I can chat with people over coffee (ok, most churches have coffee—I said that it was a poor analogy).
The relationships I have on Facebook, however, tend to have a much stronger emotional pull for me than those that I've built online. Because Facebook requires mutual consent for two people to become "friends," it keeps those relationships more closely tied to real-world ones. The people I connect with on Facebook are people that I see at work, went to school with, watched grow up, hugged, played with, and, in general, have some large level of interaction offline. Thus, the online interaction is not quite as important, but it's merely an extension of the offline relationship.
FriendFeed, by using a "follow" model, lets me interact with a much wider group of people. However, that interaction is (almost) totally online. My friends on FriendFeed are scattered across multiple nations and continentns; we can still have a laugh together, but it's unlikely that I will be invited to their weddings or funerals. Thus, those relationships are inherently more superficial than the ones I've built on Facebook.
Those two possible models of social interaction—mutual friendship or one-way following—can lead to radically different online communities. Are there other relationship models that might successfully be used to capture an audience? The only other one that immediately comes to mind is the "group" or "club." In fact, that level of organization (on the Internet) is so old as to be considered "Web 1.0" and not nearly as cool as the newer, more complex models. What does the next generation of social media look like?
