MOSCOW--When Russian clubgoers flocked to the country's biggest electronic music festival this summer, they didn't have to bring a camera or even their phones. Instead, festival organizers used facial-identification technology to pick out revelers and send them their pictures directly to their phone. All they needed to do was opt in, by sending a selfie. The technology is the product of NTechLab, a Moscow-based firm whose algorithm to identify facial features is getting attention in the broader information technology world. NTechLab co-founders Artem Kukharenko and Alexander Kabakov believe the possible uses of their technology are almost endless, and mostly positive: from allowing police to search for criminals in real time, to helping amusement parks identify and sell photos to their guests.