The sidebar in Mozilla is a handy tool to have.
You can load up a plethora of information inside of it, but why must we be limited to just using one at a time? Well, the secret here is you do not have to be limited at all. With the MultiSidebar extension you can have multiple sidebars going at once.
Put one on the top, bottom, left and right side of the browser if you want to. The only problem you mind find yourself running into is the screen space for the Web page you are viewing keeps getting smaller and smaller. Ok, so maybe running all four sidebars at the same time would be silly.
Nice to know it could be there though with this download.