While Facebook prepares to go public, Silicon Valley's other buzzy social startup, Twitter, is doing everything in its power to stay private. In pursing that goal, it has slapped its shareholders with an unusual restriction: No one who holds stock can sell more than 20% of their shares.
The rule -- which has been in place for more than a year, according to e-mails obtained by CNNMoney, but is being reported here for the first time -- has caused dissent in Twitter's ranks.
