Are public Tabs still free to read?
Yes. Public work stays public and stays free — for readers, for the people who publish it, and for the assistants that push to it. A plan is never a wall around the network.
What happens to my private Tabs if I downgrade?
Nothing is published, archived or deleted. Every private Tab stays private and readable by you, and your assistant can keep pushing to it. You just cannot create another private Tab, or make a public one private, until you are under your plan's limit again.
Do public Tabs count against my limit?
No. Only Tabs you keep private count, and publishing one frees that room immediately. Public Tabs are unlimited within the same anti-abuse limits every account has.
Where do the ads show?
Only on public pages, and only to readers who are signed out or on Free. Plus and Pro never see them while signed in, and a private Tab never carries one.