There's something similar to this in Europe, it started in france. Similar idea, except you borrow other peoples car for a fee, similar to a hire car, except you borrow someones car rather than a hire companies fleet. Except this company has its own insurance policy for a small fee that would cover you if your car gets damaged etc when you lend it out, unlike your personal insurance cover on your vehicle. I know they had a tough time getting an underwriter to agree to such a policy, but its a hell lot better than relying on this statement:
'Insurance
Passengers contributions to drivers do not generate profit, they only offset costs, therefore car sharing is not ever hire and reward. All the members of the Association of British Insurers have agreed that if your passengers contribute towards your running costs your insurance cover will not be affected. Rides must only be given in a vehicle seating eight passengers or less. BlaBlaCar scrupulously fulfills these conditions, as we limit number of seats and cap price per passengers (basing calculations on HM Revenue & Customs Approved Mileage Payment Allowance).'
As I damn well bet most insurers will try to opt out one way or another in an event of an accident, claiming they never signed such a thing with blablacar.
However if the profile pictures match up, there are some fitties, suppose it beats online dating by getting lift in random chicks cars.