Today, I unexpectedly came across this announcement from Micro.blog: Highlights are now synced to Readwise.io, provided that you have an account with them and that you are on an Micro.blog Premium plan! How cool is that!
I immediately configured my Readwise.io connection in the Bookmarks section and exported past highlights in a CSV file. Next, I tried the feature on an article from MacRumors.
After a few minutes, I could read the archived version of the article and highlight some portions. And sure enough, my highlights were saved to Readwise.io in a snap.
The nice thing is that Inoreader also supports saving my highlights to Readwise.io. Everything going at the same place. Occasionally, I export and then import my highlights into Craft. Readwise remembers the point of my last export session.