Figuring out how to evaluate pre-exercised options is to engage in the accounting version of medieval debates over how many angels can dance on the head of a pin.

FORBES: Fact and Comment

"Clearly Facebook drove the acceptance of the market, " accounting for a majority of recent trading in pre-IPO stocks on exchanges, says Christopher Yang, who specializes in technology at Grove Street Advisors LLC, a Millennium investor that advises pension funds on venture investing.

WSJ: Seeking 'Second' Life After Facebook