Facebook can only succeed in generating the advertising revenue it needs to generate if it can deliver more efficient ads and it can do this only if FB users let FB use data generated by their movements on Facebook . The world is moving towards opt-in permissions on all matters related to the Web, aided by public opinion and political pressure. You saw what happened when an employer demanded access to a Facebook page as part of the evaluation process of prospective employees. The world erupted and Congress stopped fighting itself and began to make noise to prohibit employers from doing this. Over time, you will see Google and Facebook and LinkedIn and other sites currently collecting and using data to target ads increasingly attacked by users and politicians over the issue of privacy. A corollary to this for Facebook - and not Google - is users see their page(s) as their own - and there are only so many ads and solicitations that can violate this sense of property before a certain percentage of users begin to turn off. And while Facebook and Google can lobby in Washington (worst sentence in the Constitution, that) they have no such clout in Europe, Asia or almost anywhere else.
Money can grant you new avenues of revenue. Look at zuckerberg buying random high tech companies that seem to not make since now but he's clearly thinking about the future. Advertising revenue for facebook seems like it can only go down from here and mark seems to know this. If he only uses the new tech for facebook purposes and not branching out with new services, he's an egomaniac and borderline idiot. facebook as it is will not be sustainable forever. Need to find other rev. streams