Users will be able access the feature via an “advanced mobile browser” or from the company’s new iPhone app, which is debuting today. Product manager Michael Sharon explained that when a user is at a certain location he or she will be able to look up that “place” on their phone and then “check-in.” Each “place” will also have its own page on Facebook, which will let users see what other Facebook members are “here now” at a given moment—if they have selected to share that information.

SEE ALSO: Facebook Tweaks Privacy Policy (Again) To Allow ‘Place’ Sharing

Facebook appears to have learned its lesson from its previous privacy fiascos; Sharon said the company understood that broadcasting location was particularly sensitive to many users and that the default setting with Places therefore is that check-ins will only be visible to friends and not to everyone. Users will also be able to limit access to only a few specific people if they wish.

The social network is also partnering with the three leading companies in the space, FourSquare, Gowalla and Booyah. Representatives from all of those companies were at the unveiling and explained how their services would integrate with Facebook’s. For instance, Gowalla co-founder Scott Raymond said that users would now be able share their check-ins on that service on Facebook Places and described a situation where users would be able to see “badges” they had earned on Gowalla on Facebook Places. FourSquare VP Holger Luedorf said during his own remarks that it validated “that we are on to something” and that this “will be a much much bigger thing going forward.”

By tying their services with Facebook’s, the three check-in trailblazers seem to doubling down on their identities as location-based games, which can be used to earn badges and other virtual awards, as opposed to being more general services useful for looking up where friends are at a given moment. Presumably, if what a user is really interested in is broadcasting his or her location, he or she will now do that on Facebook, where the volume of check-ins will be much greater, considering Facebook’s massive scale.

There had been reports since at least last October that Facebook was set to add a way for users to share their location in order to participate in (or counter) the momentum that location-sharing startups had gotten. Speculation that the feature would be launched at the company’s developer event this spring reached a fever pitch in March when the company updated its privacy policy to include language that would let users include location info in their status updates. But the service didn’t launch then—and Facebook managed to keep most details about what it had in the works secret.

The ongoing live-stream of the event: