My experience with Medium is the paywall is sort of random.

There's two things:

- Medium pops up a "please log in" if you've visited multiple articles in a month, but that's not a paywall, that's just an annoyance. You can dismiss it.

- For a few specific publications, the authors can choose to paywall their content after a few views. OneZero, which is published by Medium themselves, does it. This is from Marker, which also appears to be published by Medium themselves.

Yes, it's confusing for a blog platform to also run publications that accept contributions from outside writers and host those publications on their own blog platform, and have that be different from outside writers just setting up a blog. (I suppose the difference is their own publications have an editor, hopefully they pay contributors, etc.)

You can set your browser to delete your Medium cookies on exit and that usually solves the problem.