One of the tough things for anyone aiming to replicate Facebook is that Facebook used some devious methods to get up and running. Zuckerberg misapproprited hundreds of photos of his classmates and their personal information, and then sent them provocative emails that would cause most students to check on what's been posted about them, or what's been posted about others, i.e., they would visit the site.
It's like the story of the YouTube guys posting some of their own videos to get things started. Then they eventually had to upload some copyrighted content. They took a risk.
Then there's the story of Bittorrent. I believe Bram Cohen initially seeded some porn to get things kicked off.
Or the guy from ThatHigh who recently told of how he had to create fake profiles.
It seems that it is quite difficult for user contribution and sharing solutions to start from zero. Alas, you need to have content on offer from day #1. And it needs to be compelling content, in terms of quality, quantity or both.
Zuckerberg broke the rules. He stole student's personal profiles from the university's network. And he got away with it. Luck was in his favor and he knows it. Others who would try this now might not be so lucky.
Diaspora relies on people to submit their own content, but it had no compelling content to begin with. Not only did they start with no content that would draw people in, but if I'm not mistaken they expect people to run their own web servers. This is not impossible to imagine but why web servers? I guess because they want to replicate Facebook.
Solution: Don't replicate Facebook. Build something a little different. Stop thinking only in terms of web servers and web clients. Think peer-to-peer. Think in terms of application-agnostic _connections_, not applications. Do this and you instantly have something that is 100x more useful than Facebook. Because it does not have to operate within the contraints of web servers and web browsers.
But there's still that problem of compelling content...