While I agree it's a good wake-up call to people inadvertently sharing more than they'd like with the public,
I don't think it matters so much that the data was already public, so much as the way the app puts that data to use.<p>Most other location-based services have some sort of unique value proposition or special utility using the location data, or are targeted to a specific genre or use-case.<p>Girls Around Me, although you could claim it has its own "use case," does nothing more than show you <i>everyone</i> who's checked in near you, with no qualifier other than the fact that they're female.<p>This, to me, is an inherently creepy service and an aggregation aimed strictly at hormonal males, with the dangerous side-effect of exposing females who may or may not be smart enough to defend themselves.