Bookmarks are simply the present map's location, which will Zoom you to a location but not alter layer display. By clicking the on the function bar, available bookmarks display in the information panel.
In the above example we have no personal bookmarks. You can create your own Personal Bookmarks providing your browser accepts cookies. To add a Personal Bookmark for a particular location click Add Current Extent. You will then be asked to type a name for the new bookmark. Your extent will be stored for a year under whatever name you choose.
Just type in a name like "Cape Town" in the box if that is where you have zoomed in and click OK and you will see that "Cape Town" is now listed
Click on your personal bookmark at a later date, and the map will jump to that location.
To remove a bookmark, click the red cross beside the bookmark name.
REMEMBER if you delete cookies from you browser you will loose your list of Bookmarks as well. Also the bookmark will not remember all the layers you had switched on at the time you created it, so it works only on the currently selected and viewable layers.