Kotobank Captcha service becomes a bottleneck for mass registrations
When hundreds of people register at the same time, like a bulk migration from Twitter or when a group of people learn about the Fediverse and do a guided registration, the Captcha hosted at https://captcha.kotobank.ch is unable to handle the load. Since we can only scale up our own Pleroma servers but not this third-party application, it becomes an external constraint on the number of people who can sign up in a given amount of time, irrespective of the infrastructure we provision for Pleroma.
I suggest that a captcha service be included with the Pleroma installation to remove this constraint.