* "Most Visited" and "Recently Bookmarked" and "Recent Tags" are examples of so called [[Smart Bookmarks folders|Smart Bookmarks folders]] and are not real existing folders. * Smart folders show a list created by a query of the places.sqlite database that stores bookmarks and history in Firefox. * Smart folder lists show a maximum of 10 entries by default. * Bookmarks and history items that show up in a smart folder list are stored elsewhere in another folder and any changes made are applied to the real bookmark or history item. You will have to visit such a link often enough to make it appear in Most Visited. You can make the Visit Count column visible in the Bookmarks Manager (Library) via the Views menu. You can clear all history to reset the visit count.