FindFace is a very interesting piece of technology. It's legit (the authors, N-Tech.Lab, have successfully competed against google and other strong opponents in MegaFace Benchmark). It's not real-time, but fast enough (0.5-1.0 minute time required to recognize faces and provide their profile links). Their business model is freemium (first 10 or 30 searches per month are free), and they're trying to make it a matching service, you can narrow search by age and relationship status, and then you can like photos of people you find to allow searching for "your type" of partners.