[This is preliminary documentation and subject to change.]
The Microsoft® Windows® installer supports advertising of applications and features. Advertising is a mechanism whereby an application that is not installed can however be accessed as though it were installed. Only the registry entries and other necessary information are placed on the local computer. When a user activates an advertised application the installer automatically installs the necessary components as described in Just-In-Time Installation.
The installer can access an advertised feature of an installed product without the support of the user's operating system by enacting a feature level installation. The installer however does require the support of the operating system to access an advertised product that has not yet been installed, and in this case the installer must enact a product level installation.
There are two types of advertising known as 'assigning' and 'publishing.' Assigning an application populates the user interface and the application appears essentially installed to the user. Publishing, by contrast, does not populate the user interface. Another application on the user's machine however can activate the published application. The distinction between assigning and publishing is a central part of the installer's capability to enhance system management. For more information about the two types of advertising see the section Assigning and Publishing.