I've been using them for over a year.
They are legit, but require you send a picture of photo ID and a business card or some other form of ID.
I imagine you could block off certain things like exact birthday (leave the year) and parts of your address, and your License number. I think they just want a picture of you so on your first visit the provider can compare what you look like to the ID you provided.

PO is efficient and friendly as long as you are not a dick.