Looks pretty slick. I have a similar idea, but based around computability, complexity, information, games (math sense), etc. I think it's going really well, bu

Looks pretty slick. I have a similar idea, but based around computability, complexity, information, games (math sense), etc. I think it's going really well, but yeah, question quality is a huge part of the process. Absolutely dwarfs anything else. The reason I bring it up is because I think people are going to want to try before they subscribe. They're going to want to run through a few questions before they pay you any money, and they might even want to run through some questions - and quite a few of them - before they give you their email address. And that's reasonable. (Especially in my case, where I'm working on a spaced-repetition model) So the fact that you have a "Start practising" button, and I click that, and it takes me to a signup form, and then that takes me to a "here's the part where you pay me" screen kinda rubs me the wrong way. I think everything looks great. I'm interested. I was able to sign up. I received the email, and able to verify. But there's no way I'd subscribe without solid access for some nontrivial period of time to a nontrivial number of questions. Entirely possible I misunderstood something or I'm misusing the site, though - or that these issues won't concern other potential users.