none of my friends really care about cars at all, much less care about any racing games. so none for me...besides myself. I got my dad to play once. he seemed to enjoy it.
It's impossible for me to say and I've lost count of those I know about. I think my projects of the past encouraged quite a few people, I also converted a few others around me in person - in a manner similar to Populous, mhmm.
Many and with the one I couldn't I make them a deal, I bought the license for them and if after 3 months they are still playing they will pay back, small risk since they all get addicted...