While Google delivers search results selected by algorithms that take into account a user's Web history, Facebook boasts a richer level of personalisation based on one's own "likes" and the recommendations of Facebook friends.
Mark Zuckerberg, who founded Facebook in his Harvard University dorm room six years ago and is now worth an estimated 6.9 billion dollars, refers to it as the "social graph".
"I think what we've found is that when you can use products with your friends and your family and the people you care about they tend to be more engaging," Zuckerberg said in an interview with the CBS show "60 Minutes.
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"The social graph is incredibly broad," said Wedbush Securities social media analyst Lou Kerner, picking up on Zuckerberg's favorite phrase. "It includes not only what you do and what you like but people you know and what they like and the companies you interact with.
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For some Internet watchers like Kerner, Facebook is building a parallel network built around the interaction