Can someone please explain to me what a "social graph" is? I've seen lots of Web 2.0 business types talking about it, but I haven't got a clue what it actually means. 
Is it the sort of data that one would find in an XFN friends list or FOAF profile etc.? 
Or is it just some meaningles jargon people use to dscribe yet another thing to "leverage" or "synergize"? 
I just wish these Web 2.0 people would speak in specifics rather than generalities. It'd make the life of the people who actually want to implement the technology easier. That's why we like clear specifications after all... 
