A plugin is a program or set of programs created to add functionality to a larger software application. A widget is a stand-alone application that may run with a larger software application such as Sametime. You may hear these terms used interchangeably, but they mean quite different things. The Sametime SDK can be used to write to these extensions.
An example of a plugin is the Sametime wallpaper plugin found at the following site:
For more information on adding a widget to Sametime, refer to the following website: