So far I’ve had one conversation with @zzq. It was very insightful. I’d like to have a lot more interviews with potential users (hint, hint), or really anyone who uses Beeminder. I need to start reaching out to more people directly to schedule interviews instead of waiting for interviews to come to me. Probably should make a goal for that… 
https://www.beeminder.com/narthur/tr-contact
I’d also really like to switch as quickly as possible to getting feedback from real users instead of potential users, and that means MVP time. I’m thinking I could start out by sending a daily email to a group of alpha users asking them what’s on their plate for the day. They can respond back (or not) with a list of tasks and stakes for each. I’ll then enter those tasks into an AirTable base. I can generate views using the base to see what tasks are upcoming or overdue, and send email reminders to the appropriate users. If a user misses a deadline, I can manually create a charge in Stripe.
This is so ridiculously manual that I have a feeling I won’t be able to resist the urge to automate almost as soon as I start. But I think if I can resist that urge for just a little bit I stand to learn a lot by having such a high level of awareness into how the system is working for those daring enough to join the experiment.
Thankfully, once I do stop resisting, AirTable has a fantastic API, and I think Stripe has a good one too (haven’t used it), so getting the first level of automation up-and-running shouldn’t be that hard.
Beyond that, I’ll let user feedback direct the project.