The greatest issue, as you acknowledge in your post, was that you weren't testing the point closest to the sale. The first thing to test is the final registration page. I often spend a fair amount of money to drive traffic that I can optimize against to single page landing pages. If you can't make enough money through Google Ads or Facebook ads (e.g. your cost per sale > revenue per sale), then you either have a bad business or a shitty landing page.<p>Rather than just optimizing existing traffic, buy traffic and find out how far off you are. The best part of these ad systems is that they are relatively efficient. That means you should be able to quickly figure out how far you are off.<p>While I'm sure "learn Japanese" has already been taken, there are probably plenty of long-tail keywords as well as people on Facebook who haven't been targeted. Your key is going to be to find out who those people are and drive them to your site.<p>I tend to be pretty straight forward with my own investments in projects: if there's a huge gap between cost of acquisition and revenue per customer (or present value of the LTV of the customer), you probably need to build something better or change your product all together. Your own internal cost per user will end up being just as high as google ads (if not higher), except google provides an instant vehicle for testing. In other words, it will help you fail quicker ... something that's extremely valuable in the world of startups.