Get paid for your bookmarks. Get paid to be a curator.
Bookmarking or saving pages will not be a native feature. The vision is that Users will voluntarily create a "Bookmarks" page, or a "Favorites" page, etc. (they can name it whatever they'd like!) and then they can just add to that, structure it however they'd like.
Want to hide your "Favorites" page from the public? You could set it to private or to be only viewed by certain community members or user groups.
"Append this Page to <Page>"
This could be an option within a share modal, which would append the current Page to the end of some target page.
Below is a sketch with the History shown in the top section, and a "Target page" section where selection from the History pane will be appended to the bottom of whichever page is selected.
Example targets are "Favs" and "Need to read" … this is similar to playlist functionality in YouTube or Spotify, or reading lists in Safari and other browsers.

Image source: Mon Apr 10, Scanned Doc - pg 43 of journal 18
See also
Not to be confused with the concept of saving a scroll position within reading progress, which in reading apps like Apple Books or Kindle might be likened to a "Bookmark"