Given how much information is available online, why cant airbnb use, eg facebook, data for identity verification. There are face recognition softwares available now which work well in controlled environment. Of course a persons online identity may be compromised as well. But that does not mean we can not device ways to protect against such incidents using multiple checks. Eg facebook account used to create person profile of guest & host and using face recognition of facebook training dataset and real photo via webcam along with perhaps social security number we should be able to devise ways to protect against such incidents at not very high engineering costs.