All other companies work with data like "the user scrolled this far, looked at this text for this long, then clicked this button"... I have none of that on joinmastodon.org. I have no clue how people use the site, and there is no way for me to know if the Mastodon servers linked from it receive sign-ups from it or not. That is to say, its design is a blind guess and its effectiveness a mystery.
I'm considering consulting with a professional UX designer about it, but I do wonder if they'll be able to do anything without any metrics at all. I have a feeling metrics must play an important role in UX design nowadays...