What you make here
Recipes, sets, photos, bookmarks and likes are stored against your account. A recipe is private by default: it is visible only to you until you publish it.
Publishing something makes it and your public profile readable by anyone, including people who are not signed in and search engines. Unpublishing it takes it back out of the feed, but cannot recall a copy somebody already made.
Example photos you attach to a recipe, and your avatar, are uploaded and stored on the server. They are re-encoded on arrival, which drops everything embedded in the original file — EXIF data, GPS location, camera serial number. A photo on a published recipe is public like the recipe itself.
The site records which recipes are on which of your cameras, keyed by a fingerprint of the body, so it can tell you what you have already written to a slot. That fingerprint identifies a camera, not a person.