No marketing, all traffic came from search engines. I focused on SEO from the start and that helped with the rankings. I also made sure my site was more functional than the competition. 100% client-side code.
Right - The site has been running over 3 years now. There wasn't much competition at first but in the last year I've had real competition plus a bunch of copycats, some who actually copied my code and changed the front-end.