you don't need a huge number of people, you just need enough people in one rough location.
you might be able to get in contact with local community groups in an area who could benefit from the service. if you are initially targeting a particular area, you could also advertise it the old fashioned way by physically distributing notices / flyers -- i have seen this done for car-sharing services in my city.
if you initially advertise / promote the website to a bunch of people who are scattered all over the world, perhaps you'll struggle to hit a critical threshold of density for the website to be useful to anyone in any particular location.
edit: if you promote your website via something like product hunt, reddit, etc, consider the audience that you are promoting it to. are they likely to all live in a similar location? are they likely to find a car-sharing service useful? why?
edit^2: some other ideas:
* perhaps to get the first few people to sign up, you could drive them places yourself!
* you might be able to find per-city / per-town car-ownership statistics. this could possibly be useful in deciding which regions could most benefit
* you might also be able to find car traffic statistics. these could also be useful for figuring out where there might be large flows of people driving roughly the same way (i've found these before as publicly available data for my city)
you don't need a huge number of people, you just need enough people in one rough location.
you might be able to get in contact with local community groups in an area who could benefit from the service. if you are initially targeting a particular area, you could also advertise it the old fashioned way by physically distributing notices / flyers -- i have seen this done for car-sharing services in my city.
if you initially advertise / promote the website to a bunch of people who are scattered all over the world, perhaps you'll struggle to hit a critical threshold of density for the website to be useful to anyone in any particular location.
edit: if you promote your website via something like product hunt, reddit, etc, consider the audience that you are promoting it to. are they likely to all live in a similar location? are they likely to find a car-sharing service useful? why?
edit^2: some other ideas:
* perhaps to get the first few people to sign up, you could drive them places yourself! * you might be able to find per-city / per-town car-ownership statistics. this could possibly be useful in deciding which regions could most benefit * you might also be able to find car traffic statistics. these could also be useful for figuring out where there might be large flows of people driving roughly the same way (i've found these before as publicly available data for my city)
good luck!