A social networking site is only valuable to a user once it reaches a critical mass of connections. Maintaining these connections across multiple accounts is a

A social networking site is only valuable to a user once it reaches a critical mass of connections. Maintaining these connections across multiple accounts is a huge pain. None of the existing social networks have any incentive to make this process easier, whether by providing an export tool or conforming to an open "friends list" standard. Specialized Craigslist clones can exist because no one wants to sell apartment space to the same people they buy used furniture from. Friends are friends, though; if you want to share videos with them, there's a good chance you want to see what the tweet, too.