In Facebook’s first public confirmation of the talks, Thiel said the parties disagreed over price and structure when they seriously considered a deal last fall. “It became pretty clear it wasn’t going to happen,” Thiel says from the mid-Manhattan office of his hedge fund Clarium Capital. “The deal would have to be done with Facebook stock. And then you have to figure out how much the stock is worth.”

Facebook’s Thiel Explains Failed Twitter Takeover – BusinessWeek.