The more interesting part here, is that Zuckerberg being 31 years old, and having a life expectancy of 82.3 years, means the people who insisted on this agreement believe there is a significant chance of Facebook still being around 51 years from now. By comparison Yahoo is 20 years old and not precisely in its prime, and Sun Microsystems existed only for 28 years.<p>That said, it means investors are betting on FB being a long lived (software) company, such as Oracle (39 years and counting), Apple (40), Microsoft (41) or, in the extreme, IBM (105).