If you're like me, a person who likes to reinstall her system to get a clean one, you'd appreciate this add-on. This add-on syncs your bookmarks to its server on a scheduled times, and allows you to make a backup elsewhere freely. You don't need to backup manually your long-added, long-created, bajillion numbers of bookmarks.
While we're at it, this plugin requires you to make an account on its developer website. Don't fill out unnecessary information you don't want to tell.