A Foursquare-like app for China and Singapore, Youjia is a location-based application for iPhone and Android that helps users find friends and potential new friends or love interests nearby. With a very photo-focused interface, Youjia also lets you chat with any other user, making for an interesting “hook-up” experience.

Users upload photos of themselves and can check out the profiles of other Youjia users. Once another member has checked out your profile, you get a notification telling you about this person. “It makes the whole community more open and liberal, a culture that breeds more conversations and meet ups,” Willis Wee, the founder of Tech in Asia, said in a review.  

Because of its “mature” or “suggestive” themes, users must be at least 17 years old to download the application from the iTunes store. This might be one reason behind the app’s success, since it is one of the highest ranked free applications in the iTunes store in China.

According to the app’s website, you can search for people by location, gender, distance, last updated, and even “charm.” It might sound a little creepy, but many users have embraced the service. Within two and a half months of launch, the app had been downloaded more than 400,000 times.

Youjia’s business model relies on virtual goods. Users can buy credits to send each other virtual gifts to express interest or flirt with other Youjia members. In the virtual gifts store are rings, bags, cameras, rings, virtual iPhones and other gifts icons that users can collect.

Youjia is a Shanghai-based startup that launched in fall 2011 and was developed by Shanghai Zhanyi Network Technology Co. By December 2011, it had raised $3 million from a Taiwanese investor, according to Tech In Asia. Youjia is one among many social networking/hook up apps such as Mix, Mojing and Momo.