Moving to challenge Google and other emerging location-based services, Facebook on Wednesday introduced Facebook Places, a way for users to expose their location to other Facebook users and applications and to locate their friends.
Places allows users to share their location in real-time using an iPhone or a Web page accessed through a mobile browser that supports HTML 5 and geolocation.
By accessing Places through Facebook's iPhone app or the touch.facebook.com site and pressing the "Check In" button, the user sees a list of nearby places. He or she can select an existing place, search for other nearby places, or add a new one.
Checking in sends a message to friends' News Feeds and shows up in the Recent Activity list associated with the relevant Place page.
Places also allows users to tag friends who are present in a location, just as they can tag friends in photos posted to Facebook.
The service is currently available only in the U.S. but Facebook is working to make it more widely available.
Facebook is exposing Places data to developers through its Graph API. It anticipates developers will employ Facebook users' location data to enhance the social experience of various mobile and Web applications.
The company also anticipates criticism from privacy advocates, as can be seen in its insistence that there's no privacy risk associated with Places. "It's important to remember that all access to location information through the Graph API respects a user's privacy controls, which can be viewed and changed on Facebook.com or m.facebook.com," explained Facebook Places engineer Ben Gertzfield in a blog post for developers.