Determined to keep Facebook away from Google, Microsoft CEO Steve Ballmer offered to buy the company in 2007. Steve knew Mark would never relinquish control over Facebook, so he came up with a deal based on Hoffman-LaRoche's acquisition of Genentech.
Kirkpatrick explains, "Microsoft [would] acquire a small stake in Facebook at a $15 billion valuation. Then, Microsoft would have the option, every six months, to buy another 5 percent of Facebook. A complete takeover of the company would take 5 to 7 years."
The acquisition never happened, but Microsoft did buy 1.6% of Facebook for about $250 million. That deal, which set Facebook's value at $15 billion, stipulated that Facebook would have to give Microsoft notice if it ever began to take a buyout offer from Google seriously.