n Extends the functionality of the host
application
n Usually running in-process (I.e.
contained in a DLL)
n Usually a visible component embedded
into a dialog/window of a host application
n Controlled through an automation
interface
n Language independent
u Uses a binary type library
u Does not require header files or libraries
u Works in many development
environments, e.g. Visual Basic, Visual
C++, Delphi, Internet Explorer