I think you're greatly underestimating the value of Google's content network, and display advertising in general. While the majority of Google's ad revenue still comes from search, Google's display advertising is sizable, and growing quickly. In fact, it's the fastest growing advertising segment for Google, having doubled last quarter to a $5B annual business from $2.5B annual business just a year ago. The crazy thing about this is that while Google “owns” the vast majority of web search advertising, they still only control less than 10% of the webs display advertising. Source:<a href="http://adage.com/article/digital/search-drives-google-display-ads-a-5-billion-business/232242/" rel="nofollow">http://adage.com/article/digital/search-drives-google-displa...</a><p>Remember, Google's content and display advertising technology is only in its nascent stages relative to its Search technology. Display advertising technology is a little trickier than search advertising, as search advertising by nature of its use of keywords has targeting built into itself. Good display advertisement targeting requires the conflux of accurate user data, accurate interpretation of web content, and the understanding of advertisers goals. In some regards, it seems Facebook has a much better system to meet these needs, or at least, the potential for a better system.<p>On top of that, you also have to keep in mind the almost exponential growth we’re seeing in mobile platform usage. I would posit that social applications are going to make much better platforms for mobile advertising than mobile search. Just anecdotally, consider the amount of time that you and your peers spend searching on your mobile phones or tablets versus the amount of time you spend say on Facebook or social new aggregators. I would assume your social apps usage is much higher. Also, now consider from the user experience perspective how poorly advertising on mobile search would be. The times you’re searching on a mobile device is generally more often out of immediate needs, and if a user is getting an advertisement in such a rushed condition, especially with limited screen real estate, it’ll make for a much greater inconvenience than being interrupted by an advertisement while browsing a social app.