I don't think this signals a victory for Foursquare. Do they even make any money? I don't use the service myself, but my only interaction with it is rampant annoying updates from people I barely even know on Facebook. I never thought the "check-in" was a terribly useful feature anyway, but more of a cool new display of the power of geolocation.
I always thought it would be far more useful to build these services out as a way to allow people to quickly find each other in one-to-one, as opposed to unsolicited one-to-many, updates. For example, I think a more common use case would be to pull out a phone and alongside a contact have a single button to query for location, then on the other end have the user just as easily transmit his or her location. That would fix the privacy concerns as well.
I always thought it would be far more useful to build these services out as a way to allow people to quickly find each other in one-to-one, as opposed to unsolicited one-to-many, updates. For example, I think a more common use case would be to pull out a phone and alongside a contact have a single button to query for location, then on the other end have the user just as easily transmit his or her location. That would fix the privacy concerns as well.