I wanted to reduce the signup friction as much as possible, but a few assumptions of mine that perhaps you debunked: (1) I thought the front page and the image

I wanted to reduce the signup friction as much as possible, but a few assumptions of mine that perhaps you debunked: (1) I thought the front page and the image of the 2 tweets was the demo (at least it was enough to describe the benefits of this service/app to the prospective user). If you try to add an entry, there are examples to guide you. When you say a demo, do you mean a YouTube clip showing how it works? Specifically, did you want to know (a) what this does and/or (b) how to use it ? (2) Technically, if you click 'sign in' from the main page for the first time, you're then showed a 'sign up' page (which if you leave the site at that point, your account is not created. But then again, it's what the user thinks happened that matters :)