Lately blablacar has been charging hitchhikers/travelers up front. So you as a driver know for sure you won't end up with nothing. This is really useful IMO, but also mostly significantly reduce the popularity of the service in places with low reliability among members.

In western Europe, particularly Germany, it was still very easy to find people, in eastern Europe, not so much. Even though before this change, years ago, blablacar was very popular in said eastern Europe countries.