While I can appreciate (in fact, I probably don't) the technical difficulty of delivering a chat/video service to a userbase of 750M; these simply aren't compelling innovations for most (especially younger) people. Of particular note, these features aren't sticky (the usability of these features is common to _many_ other services) nor do they raise particularly high barriers to entry for competitors (Google has alrea…
Most people's social graphs are too small (130 people) to be useful. Well we will use an extended social-graph, you might say, but if you are extending the social-graph, why not include the entire internet? Why would my social-graph contain better (more accurate and relevant) information about doing a thing than doathing.com? The social-graph is a reduced set of the internet. It is probably easier to search, but how…
You have control of your own social graph, you don't have control over who puts a page up for Google to crawl. You're using the authority someone has as part of your network to filter what comes in to the network - search only on sites that friends-of-friends have recommended and you're unlikely to get spam or sites that are hard to navigate or that won't provide a good service. If I'm looking for new outdoor equipment I could look at the online stores that fellow scouts have used and recommended and so save time weeding out the better stores.
Just my immediate reaction to your question. There are clearly benefits in both types of search. Also this presupposes that FB aren't trying to inject advertised offerings in to your social-graph based search; probably a bad assumption as that there looks like gold to me.