[sumeno]

You could provide a one stop shop for sharing information with the people you care about that is easy enough to use that even people who are afraid of technology can handle it... also everyone they know needs to already be on it... but then you just created Facebook.

The ease of use is only one part of the problem, the other part is that you are trying to solve a problem that a lot of people who use Facebook just don't care about. Facebook fills their need and they really don't care about walled gardens or open internet or whatever else the HN crowd views as a dire issue.