Social networking sites generally try to keep users trapped within a walled ghetto. Users are an asset. Sites do what they can to avoid sharing their user information. Sites often try to limit links out to other competing sites.

This is in direct conflict with users needs. Most ordinary folk are naturally members of many communities. You might be a parent of school age children. You live within a neighborhood, city, county, state and country. You might have interests in photography, genealogy, hiking, dating, religion, aviation - each of which is likely a largely-separate community from the other. Discounting the craze for kewl “handles”, you probably want to have the same basic identity - your identity - across all these communities.

Which makes this comment somewhat off target…

Google Working on Social Network Aggregator From my perspective, I’m skeptical of a lot of the talk about social network portability because the conversation rarely seems to be user centric. … [snip]

A real social network is a community and users don’t change communities at the drop of a hat. What I find more interesting is being able to bridge these communities instead of worrying about the 1% of users who hop from community to community like crack addled humming birds skipping from flower to flower.

Users interact with different “communities” all the time! Any one site is unlikely to capture (a loaded word) all of your interests. You might be unlikely to “hop from community to community” for any one particular interest, but for disparate interests - such “hopping” is almost guaranteed.