I used to subscribe and use #Readwise (Reader.io). It was pretty ground breaking for highlighting and saving bits of articles etc. I wasn't using it to its potential, so I ended my subscription awhile back.
They've been quiet with any email updates, feature additions, etc. for like 8 months.
Today I get one and every new Public Beta 'improvement' revolves around #AI. Surprised? 'Ghostreader' is one of them:

"Ghostreader now indexes every word of every document and can instantly generate cited answers for you across your full library. Beyond just answering questions, however, Ghostreader can also help you triage your inbox, organize your library, and act as a full-powered reading assistant for you."