Lore has it that while Mark Zuckerberg was able to turn down Yahoo's $1 billion offer to buy Facebook in 2006, his board and investors would have forced him to sell if Yahoo CEO Terry Semel had come back with a $1.1 billion offer.

According to a person who was in the room with him when he made the decision, Terry was adamant he would not up the offer.

Today, four short years later, we learned that, with the help of Goldman Sachs, Facebook plans to sell just 4% of the company for twice as much as Yahoo's highest – a $2 billion raise at a $50 billion valuation. Guess Terry got that one wrong. (But boy did Mark get it right.)