After another session of using Arbital, I have a few questions and comments.
1.) Is there any mechanism for citations? There probably should be. A lot of what I have written about order theory so far is inspired by Davey and Priestly's Introduction to Lattices and Order. I don't think it's realistic for someone to pull an entire tutorial on a mathematical topic directly out of their brain.
2.) I love the hover-over definition display. It's very convenient for looking up definitions without having to transition to other pages.
3.) It seems that it would be useful to be able embed arbital pages inside of other arbital pages. Here's the motivation. Let's say that I have a definition of poset, much like the one in this order theory tutorial, but in its own page. It's convenient to have short definition pages (like this one) for use with hover-over. However, in this order theory tutorial I don't want to replace the definition of poset with a link, because it's an important part of order theory and there may be other text on this page that refers to it. Yet we still want to give the definition of poset its own page. Right now, it seems that the best way to do this involves redundancy: have two poset definitions, one embedded in the tutorial, and the other on its own page, including essentially the same content. This redundancy does not seem ideal. This feature sounds like it would be a nightmare to implement, but it would be really useful.