Because BlaBlaCar is NOT a taxi service. They can't operate in Europe as a Taxi service, as it will be illegal to have a Taxi service without the proper permiss

Because BlaBlaCar is NOT a taxi service. They can't operate in Europe as a Taxi service, as it will be illegal to have a Taxi service without the proper permissions, paying proper taxes, etc. So they are doing REAL car sharing. Some one helps you to pay for the cost of the trip, and that's it. It's the old car pooling but more teachy.