a type of Walled Garden?
if you're building one, it makes sense to
- have human able to read infinite number of meta-content pages - navigation pages, etc.
- allow any piece of content to get read if reader is following a link from another site
- use a Metered Pay Wall to limit free use
- allow some WebSpider-s (e.g. Google) to index everything on the site. (Heck, I did this for MedScape in 1998 or so...)
- note that these "exceptions" create an easier opportunity for a "hacker" to defeat your paywall, but it's worth it.
for reader to escape one: https://archive.ph/