Someone posted that link here recently and it was very useful, but unfortunately the blog doesn't link to the next one in the series. Here it is: https://blog.joinmastodon.org/2018/07/how-to-make-friends-an...

It sounds like the series was intended to continue, but I painstakingly clicked through the blog and couldn't find any more.

From my side, the thing I am most interested in is some kind of micro-plugin that could be used to ActivityPub-ify an otherwise static site, maybe a bit like the old guestbook functionality from Geocities days. It would be cool to be able to just upload your site in a static way and have a hook that publishes that update out to your friends, and catches any of their comments in an iframe on the page.