Traffic from ChatGPT now brings a quarter of our sign-ups. How we track it, and what we changed

In April, 3.7% of new members on my website came from ChatGPT. In September so far it is 24.5%, and last week it was one in three. Here is the share week by week, why we couldn't see it at first, and every change we made for AI search, in the order we made them.