Facebook The Patent Buyer: Even Before IBM, The List Includes HP, Friendster, BT? And Halliburton

Facebook, according to reports, is buying up a boatload of patents from IBM -- 750 in all -- that will help the company shore up against potential attacks from other companies claiming the huge social network infringes on their intellectual property. But for the past couple of years, Facebook has already been taking steps to build up its patent portfolio through the acquisition of patents from a host of other players, from large IT companies, to a patent troll and a defunct social network. And a few surprises.

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