Something super small that I've noticed in the guestbook: since there're a lot of people connected, I noticed that every time I received an update, I lost the focus of my text element, so it was a little bit difficult to write something.

It may be annoying if two users are working at the same time in the same project.

Again, very cool project! :)

Yup, I've made a note of this and will fix it once the Show HN traffic eases off a bit. Thanks for the feedback and the kind words!