If you are the owner of a site, you can change whether the sidebar shows, where it shows, and what gadgets are included in it.
You can get to the "Site layout" tab to edit your sidebar in one of two ways.
Once you are on the "Site Layout" tab, you can change the location of your sidebar or turn it off:
Once you are on the "Site Layout" tab, you can add various gadgets to your sidebar by clicking Add a sidebar item, then selecting a gadget from the list.
You can edit or delete any item in your sidebar by clicking on edit or delete below the item.