A set is private until you change its visibility to public. Once it is public, anyone can find it in Explore, study it, and copy it into their own account. A copy is independent of your original — the person who took it can edit their version freely and nothing they do reaches yours.
What stays yours
The set itself. Other people cannot edit your set, only take a copy of it. Your study history is also yours alone: mastery, review dates and the record of what you have got wrong are attached to your account and are not part of what is published.
So publishing shares the words, not your progress through them. Somebody who copies your set of four hundred terms starts every one of them at mastery zero, exactly as they would with a list they typed themselves.
Why copy rather than subscribe
Because a shared set that keeps changing underneath you is a problem for a schedule. If the author reworded fifty definitions in week three, the words you had driven to mastery would silently become different words, and your review dates would be describing something that no longer exists.
A copy freezes that. The trade-off is real and worth stating plainly: you also do not receive the author's corrections. If they fix a typo next month, your copy keeps the typo.
What makes a set worth publishing
Sets that other people can use tend to have three things: a title that says what is in it and for whom, definitions in one consistent direction, and example sentences. The third is the one most public sets are missing, and it is the difference between a list someone studies twice and one they finish.
Why examples matter, and two ways to add them
Public sets can receive likes, and there are badges for reaching ten and fifty of them. Treat that as a rough signal of usefulness rather than a target — a set built for your own exam is allowed to be useless to everyone else, and keeping it private costs you nothing.
Before you publish
Check the set for anything personal. Words saved out of a book you uploaded arrive with the sentence you met them in, which is fine for a novel and less fine if the source was something private. Uploaded books themselves are never published — only a set you explicitly make public becomes visible.