Very nice. As a UX person who recently got into data science this is a breath of fresh air compared to the traditional jupyter notebooks. Website looks really fresh and I love the colors and font usage. Video could be slightly shorter to really show me the highlights and maybe show a bit more of the realtime collab (althought the gif below shows it well).

One thing that annoyed me a bit is that I could only register with github or google. Why can't I just create an account directly with your service?