Bookmarks are one of the special features you receive when you buy a Plus account. They allow you to quickly and easily navigate through a list of your friends (or enemies) without having to slog through galaxies and planets in the Galaxy tab.

To add an empire to your bookmarks, navigate to their empire page and click the button that says, "Bookmark". They will now show up in your list of book-marked empires. To reach the list click the "Bookmarks" link, which is located next to the News and Mail links at the top of your 'My Empire" page.