inbound - 8:46 pm on Jan 15, 2013 (gmt 0)
We must look at this from the standpoint of an average user of Facebook. It's far too easy for us to dismiss things that we don't like as webmasters.
I believe that most (average) users of Facebook will have some interest in the things that Graph Search can do for them, and if they like what they see they will use it more and more. Many people use the internet to arrange their social lives, the connections that Graph Search provides will help people do that. Another thing to bear in mind is that many people have lots of "Friends" so it's not inconceivable that bizzare search combinations will work and uncover connections that will turn out to really matter to the user. If Facebook can make people care about their search product (because it gives them a way to find people that they share unknown passions with) it's going to be something that gets used a lot.
It's always tricky to predict how things will pan out, but I'd say that people will quickly see that this can do things which Google cannot. It remains to be seen whether the lure of a search that's based around arranging your social life will tempt people to enter other types of search (to be answered by Bing from the same search box).
The way I see search is that some things/searches are more important to people than others. Do you care more about the quality of results for your favourite hobby or for a random, average, one-off information need? Searches for things people are passionate about (which very much includes their social life if a regular Facebook user) are much more important - and if someone just wants to use one search engine they will choose the one that answers those questions best, whilst accepting good (but not neccesarily excellent) results for things that are of less consequence.
This is going to put more pressure on Google+, as the fragmentation of the search market may be reliant on which social platform can keep its users. A worrying thing for Google is that each new, young, internet user is likely to be a heavy Facebook user - they have the older generations locked in but time may see them decline due to social being a primary online activity for younger users.