The following is an excerpt from my Dentalcompare article. Follow the link for the whole thing.
…There it is, “dentists my friends liked.” With Graph Search a patient “like” becomes far more valuable than it was before…
With Graph Search the person looking for a dentist … can search their social graph to see which dentists their friends like.
Compare this with a typical Google search. If you type in the word dentist into Google you will get a list of dental referral sites as well as some dentists in your area. Which dentists show up? Those who are Internet savvy have paid a web designer for good SEO and or paid Google to show up on a PPC ad. Are those dentists any good? Will you like them?
With a social Graph Search you are finding dentists your friends use and like. It is much more like an actual personal referral than a random Google search.