Understanding Portal Desktops 
For portal users, a portal desktop defines the structural layout and design of the portal workspace displayed on the screen. It is a structured collection of iViews, pages, themes, and layouts, which can be personalized at runtime.
In the design time environment, a portal desktop is a collection of framework pages and portal themes, which is defined and customized by content and system administrators, and ultimately assigned to portal users through portal display rules.
Framework page: Defines the layout of navigational and structural elements in the portal desktop. For more information, see Understanding Framework Pages.
A portal desktop may contain more than one framework page. The administrator responsible for configuring the portal desktop object sets the active framework page.
Portal theme: Defines the overall look-and-feel of user interface elements in a portal desktop, such as color, contrast, and font usage. For more information, see Understanding Portal Themes.
A portal desktop may contain more than one portal theme. The administrator responsible for configuring the portal desktop object sets the default portal theme.
Portal desktops combine personalization and scenario-based options for portal users at runtime:
The flexibility of framework pages enable administrators to design custom-made navigation layouts that suit various portal user experiences. For example, thin desktops can support dial-up connections, while customized framework pages support different navigational needs for a company's employee intranet and customer-based extranet.
Portal users automatically receive the appropriate framework page based on transparent display rules, which are predefined by the portal administrator. See Understanding Portal Display Rules.
Administrators assign multiple themes to a desktop to provide portal users with the freedom to choose a portal theme to personalize the look and feel of their portal desktop.