Windows 7 provides a Gadgets Platform which is used to create and host Windows 7 gadgets. Some of the goals of the Gadgets Platform development was to provide excellent backward compatibility with existing Windows Vista gadges, while providing many improvements for gadget developers including better debugging and better gadget management.
An interesting feature provided by the Gadgets Platform is the ability to add an installed gadget to the desktop programmatically. So, for instance, if you write an application that has a corresponding gadget, you could have an option to install that gadget on the user's desktop as part of the installation procedure. This would make it easier for the end user to access your application quickly.
Gadget Management has been simplified by eliminating the Sidebar container, and adding a 'Gadgets' link to the desktop context menu. By removing the sidebar concept, the gadgets just dock directly onto the desktop, without having the option of putting them in the Sidebar container or the desktop. The 'Gadgets' link from the context menu opens a gadget management window where the user can install, uninstall, and search for additional gadgets online.
Additional information about the Gadgets Platform improvements and gadget development on Windows 7 can be found here:
http://msdn.microsoft.com/en-us/library/dd370867(VS.85).aspx
http://msdn.microsoft.com/en-us/library/dd378389.aspx
http://msdn.microsoft.com/en-us/windows/dd239181.aspx