You have read an article, and there is an update or correction.
Use a cookie to identify the visitor, and alert them while they are next visiting your website about articles they have read and have been updated so that they can see the correction.
You just handed your car to be serviced, and you are waiting in their lounge for them to finish their work and hand it back to you. You don’t really know what is happening and how long it will take.
An app that both the mechanics and you use. The workers use it to signal what the plan of action is, where in the plan are they now (what specifically are they currently working on), and a schedule and finishing estimate for each step and the whole plan. You get to see (with alerts or by checking the app) where they are in the execution plan, and time estimations as to when they’ll finish.
Books, even ebooks are fixed things. What you get is a finite product of that edition. Most likely by the time you read it, at least some things have changed.
Create a format that allows the author to push new editions to current buyers of previous versions. The reader will get an alert that he has now a new edition; a brief description of the changes and additions; and the possibility to read any of the editions published, and at any point also see the current text’s other edition versions.
If they are getting less and less traffic, you might want to update and upgrade them (new information, graphics, etc.) Why not get paid for doing so?
Offer other blogs the option to buy the use of your new and upgraded post, then upgrade and update the old post, publish it on your blog and let other blogs who paid publish it (with proper attribution) on their blogs.