An add-on can put its icon on the bar automatically if it likes, but some add-ons do one of the following: * Add an item to the Tools menu * Add an item to the right-click menu (depending on the context) * Put a button in the button palette so you can add it to a toolbar if you like (''to call up the button palette, use'' View > Toolbars > Customize ''or right-click a blank area after the address box on the Navigation Toolbar and choose Customize from the pop-up menu'') Also, you might want to double-check that the add-on is enabled. Tools > Add-ons > Extensions If you have the orange Firefox button, it's Firefox > Add-ons > Extensions Does that help? (If you have problems with a particular extension, you could mention which one it is for more specific comments.)