"I first came across the phrase social graph in 2007, in an essay by Brad Fitzpatrick, though I'd be curious to know if it goes back further.
The idea of representing relationships between people as networks is old, but this was the first time I had thought about treating the connections between all living people as one big object that you could manipulate with a computer.
At the time he wrote, Fitzpatrick had two points to make. The first was that it made no sense for every social website to try and recreate the same web of relationships, over and over, by making people send each other follow requests. The second was that this relationship data should not be proprietary, but a common resource that rival services could build on as a foundation.
Fitzpatrick subsequently went to work for Google, and his Utopian vision of open standards and open data became subsumed in a rivalry between Google and Facebook. Both companies now offer their version of a social graph API, and Google (which is trying to catch up) has taken up the banner of open standards and data portability.
This rivalry has brought the phrase 'social graph' into wider use. Last week Forbes even went to the extent of calling the social graph an exploitable resource comprarable to crude oil, with riches to those who figure out how to mine it and refine it.
I think this is a fascinating metaphor. If the social graph is crude oil, doesn't that make our friends and colleagues the little animals that get crushed and buried underground?"