Facebook photo search is a good way to learn graph search, since it's easy and fun to try to find photos on Facebook.
Let's look for pictures of animals, a popular image category on the world's largest social network. To start, try combining a couple of structured search categories, namely "photos" and "my friends."
Facebook obviously knows who your friends are, and it can easily identify content that fits into the bucket that's considered "photos." It also can search keywords and has basic photo-recognition capabilities (largely by reading captions), allowing it to identify certain types of images, such as animals, babies, sports, and so forth.
Type a Query, See a Drop-Down List of Phrases
So to start, try typing simply, "Photos of animals my friends," specifying those three criteria - photos, animals, friends.
The image above shows what Facebook might suggest in the drop down list of queries as it tries to imagine what you're looking for. (Click on the image to see a larger, more readable copy.) The drop-down list can vary based on your personal Facebook account and whether there are a lot of matches in a certain category. Notice the first three options shown on the right above are asking if you mean photos your friends took, photos your friends liked or photos your friends commented on.
If you know that you want to see pictures your friends actually posted, you can type into the search bar: "Photos of animals my friends posted."
Facebook will suggest more precise phrasing, as shown on the right side of the image above. That's what Facebook showed when I typed in that phrase (remember, suggestions will vary based on the content of your own Facebook.) Once again, it's offering additional ways to narrow the search, since that particular search would result in more than 1,000 images on my personal Facebook (I guess my friends are all animal lovers.)
The first drop-down query option listed on the right in the image above is the broadest one, i.e., all photos of animals posted by my friends. If I click that option, a ton of photos will appear in a visual list of matching results.
At the bottom of the query list, two other options are asking if I'd rather see photos posted by me that my friends clicked the "like" button on, or photos posted by my friends that I clicked the "like" button on. Then there's the "friends who live nearby" option in the middle, which will mainly show photos taken near my city. Facebook also may list one or more groups you belong to, cities you've lived in or companies you've worked for, asking if you want to see photos from your friends who fall into one of those buckets.
If you left off the "posted" in your original query and just typed, "photos of animals my friends," it would likely ask you if you meant photos that your friends posted, commented on, liked and so forth.
What Facebook Search Does Behind the Scenes
That should give you the basic concept of what Facebook is analyzing when you type a query into the box. It's looking mainly at buckets of content it knows a lot about, given the kind of information Facebook collects on all of us and how we use the network. Those buckets obviously include photos, cities, company names, place names and similar structured data.
An interesting aspect of the Facebook search interface is how it hides the structured data approach behind a simple, natural language interface. It invites us to start our search by typing a query using natural language phrasing, then it offers "suggestions" that represent a more structured approach which classifies contents into buckets. And it buries additional "structured data" search options further down on the result pages, through filters that vary depending on your search.
Refining Your Search Results
On the results page for most queries, you'll be shown even more ways to refine your query. Often, the additional options are shown directly below each result, via small text links you can mouse over. It might say "people" for example, to signify that you can get a list all the people who "liked" a particular restaurant after you've done a search on restaurants your friends like. Or it might say "similar" if you want to see a list of other game titles similar to the one shown in the results list for an app search you did involving games.
There's also a "Refine this search" box shown on the right side of many results pages. That box contains filters allowing you to drill down and narrow your search even further using different parameters, depending on what kind of search you've done.
Graph Search: Not a Typical Web Search Engine
Graph search also can handle keyword searching, but it specifically excludes Facebook status updates (too bad about that) and doesn't seem like a robust keyword search engine. As previously stated, it's best for searching specific types of content on Facebook, such as photos, people, places and business entities.
Therefore, you should think of it a very different kind of search engine than Google and other Web search services like Bing. Those search the entire web by default and conduct sophisticated, mathematical analyses in the background in order to determine which bits of information on particular Web pages will best match or answer your query.
You can do a similar web-wide search from within Facebook graph search (though it uses Microsoft's Bing, which, many people feel isn't as good as Google.) To do a web-side search on Facebook, you can type web search: at the beginning of your query right in the Facebook search bar.
Advanced Facebook Search Learn more about Facebook's new search capabilities in our guide to Facebook advanced search.