AMZN) as a guide for how both companies may navigate post-IPO life. As with Amazon's turnaround from a poster child of the dot-com bust -- to one of the most watched growth stocks in the U.S. -- the key for Facebook and Groupon will be to continue experimenting with business and revenue models even if Wall Street decries the uncertainty. Schlein says one of the best lessons he's learned in his career as a venture investor comes from Amazon's Jeff Bezos, arguing that it is applicable to Facebook and Groupon as they try to overcome a rough first year in the public spotlight. The key, he says, is as Amazon differentiated itself from online retail competitors and is now a credible challenger to Apple's ( AAPL) dominance in the tablet and mobile market, Bezos stuck with his bold plans for the company, shrugging off Wall Street skepticism. As Schlein puts it, Bezos's perspective in building Amazon was, "this is our plan and what we are going to do. Wall Street can come for the ride." For Facebook, which still needs to better position itself on mobile devices and figure out how to monetize a base of nearly a billion users, Amazon's path to success is instructive. To eventually impress Wall Street, chief executive Mark Zuckerberg should continue to invent and experiment with the social network, unlocking the revenue opportunities that will satisfy investors without alienating customers. For instance, Facebook has built a strong presence in "identity," which is to say that consumers can log into an array of Web products like Spotify, newspaper subscriptions and mobile apps simply using a Facebook password. It's an unheralded function in Facebook's growing Web dominance, which Schlein says may yet prove to be a strong revenue source. "I think it is a big deal that people haven't thought about," he says, of the technology.