Los Angeles looks to be a hot market for online dating apps, as yet another, mobile dating app--Hinge, said it has launched in the city. Hinge--which comes out of New York City--said it is launching in LA today, to help single, young professionals meet others in the city. Hinge is focused on connecting people via their extended, social network, saying it uses Facebook validated profiles and a user's social links to help them meet people they will actually like. Hinge said it targeted Los Angeles for the launch, because it found that LA is "officially the hardest place to meet new people." Unlike native LA dating app Tinder, Hinge uses things like friend sin common,interests, religion, and other factors to help match up potential dates.