FTM's work if you have the content (and continue to create it) that people are willing to pay for. As for finding your site, that's what Bing and Google do. As to how long it will take to reach 10,000... your guess is as good as mine.
Users need to find you either via the web (SE, links, ads) or via word of mouth, radio, print, tv advertising... You do NOT want the search engines accessing your pay content or you might as well not be in business. You will want a few pages indexed to let people know what is being offered, what the fees are, and the length of time per subscription/membership as well as a subscription page and log in page. These face out to the net (and the search engines), everything else is under lock and key!
FTM sites are moderately difficult to secure, may be expensive to operate (funds or time or both), and require dedication to create, and CONTINUE to create, content folks will purchase. Research similar sites to see how they are set up, how you found them, and take notes of what appears to work and what doesn't.