This is applicable to all browsers having a bookmarks bar.
Fill the bar with folders named in terms of topic groups e.g Email, Weather, Forums, Misc etc.
When selecting an item to be bookmarked, a panel comes up asking which folder you wish to save it in.
Bookmarks are then saved by appropriate folder or group.
Clicking any folder will show the drop down of all items in that folder.
See image - the drop down shown is for the HOME folder.