Hi Alex, I shared the SE link here to help with donations and I hope it's working.

Thank you for your beautiful project.

For a few years, every January 1st, for public domain day, I have been promoting SE on social media, the thread on Mastodon is the one with the most involvement. https://fosstodon.org/@paulox/111680544393923401

It would be nice to have an SE account on Mastodon that posts about every new book published, since IMHO it's the social network more aligned with the spirit of SE.