Facebook is rolling out its internal Graph Search engine to all users. Graph Search has been in limited beta since the beginning of the year, it allows users to search across Facebook very much like how you'd use a search engine like Google. For example, you can do a search for 'ice-cream parlors near me' and Facebook will return a list of ice-cream parlors who have Facebook pages. Even better, you can do a search for 'ice-cream parlors my friends like' to get an idea of what's good.
It sounds like a good idea so far, but you can also search with less innocuous search terms. A search for 'photos of single women' for example, returns a photo gallery of single women, not all of whom are my friends.
It's important to note that Facebook isn't suddenly revealing content to Graph Search and changing your previous privacy settings. Different users will see different results, based on the access they have with their friends. Running a search, I might be able to see photos from a friend of mine, but a friend of a friend might not if the photos haven't been shared with him. Only content that's been set to public will be available to anyone running a search.
However, not everyone might know the extent to which their information is being shared. That's why you should revisit your Facebook privacy settings today to see just what it is you're sharing with the world and Graph Search. You can also click the lock icon on the top right of your Facebook home page for a quick review of your privacy settings and set who can see your posts and how your profile would look like to a non-contact. You can also check your activity log to see the posts that others have tagged you in and confirm who can see them.
Facebook also has a search privacy page, with more information on privacy settings for Graph Search with three video guides to follow along.