SecondMarket, a New York-based company which provides an exchange, for some 35,000 qualified investors, to buy and sell shares in private companies, has seen demand double in the fourth quarter of 2010, Erick Schonfeld reports this morning at TechCrunch.

In May, we interviewed Jeremy Smith, the company's chief strategy officer, about the company and its busines model.

Separately, Bloomberg News reports that LinkedIn could be worth as much as $3 billion in the secondary market, according to SharePost, another exchange for private shares.

Andy Plesser