>These identity verification services look like a scam to me.

Even if their intent is to run an 'honest' business, the method of bouncing a user around to god knows how many domains during the process becomes effectively indistinguishable from a compromised service, and the alternative of having each site host their own id verification system screams, HACK US. I can see users becoming increasingly accustomed to getting out their cards several times during a sign-up and not having the foggiest idea of where their information went to.