Drop anything in the Sidebar: images, uploads, Calendars,
Widgets, Documents, Blogs, Podcasts...
A Layout here becomes a list of links to whatever is inside it,
while Web Pages displays in their entirety. The Sidebar is also a
good place for Widgets - click the Picker in the File Manager for a
list of available Widgets.
Note that Widgets will only display
when the Sidebar actually is a Sidebar. If you use the Sidebar as
a Footer, it will only display Documents and Layouts. If so,
create Widgets into the SiteFooter Container instead.