the massive fragmentation problem that I currently have with social networks.I've always thought that the tendency to view social network fragmentation as some sort of problem, rather than as a rather useful feature, is a major blind spot for programmers. This Buzz debacle does nothing to discourage that hypothesis.
I blame the database training. After you've spent enough time wrestling databases you begin to dream of putting the universe into normal form. You envision a world where every piece of data might be seamlessly linked to any other with some sort of super-powered JOIN command. This is the dream that leads people to think that single-sign-on across the entire web would be a great thing. Unfortunately, this dream is also Orwell's nightmare.
I have a lot of friends. Some of them are elderly former carpenters who have never used computers. Some of them are college-aged aspiring hackers. Some know me personally. Some know me mainly as a pseudonym on HN. Some of them are middle-aged hippie folk musicians. Some of them work for major military contractors. Some of them are professors on the tenure track. Some of them barely have a high school education. Some of them are millionaires. Some of them are unemployed. Some of them are theoretical physicists, but many more of them loathed high school physics.
I have no particular desire to put all of these people in the same room at the same time. The one occasion where I was compelled to approximate that even slightly -- my wedding -- was the occasion of more than a little stress, despite every single guest's friendliness and good cheer. Because it's really very difficult to throw a party where everyone you know feels equally welcome.
I would not be surprised to discover that social networks are going to remain fragmented because most people like them that way.