One factor favoring secondary buyouts is that they can be completed more expeditiously than an IPO or a sale to a strategic buyer can.

FORBES: Private Equity Deal Supply And Range Will Increase

By contrast, Buyer says, Facebook is going the traditional IPO route.

FORBES: Facebook's Pop and How To Play It

While the initial investors may be prepared to stomach that, executives need to reassure employees that the stock price in early trading isn't essential to the long-term prospects of the company, says Liz Buyer, founder of Silicon Valley-based IPO consulting company Class V Group.

WSJ: The Art of the IPO