A portal application is responsible for aggregating multiple sources of information content, customized for each user's needs and context.
If the content is in XML, then XSLT stylesheets can be used to filter, restructure, and present the same source customized for each user or device.
Content management includes definition of the XML vocabulary, creating content according to that vocabulary, and assigning additional metadata that facilitates searching and personalization.
Portal design includes specification of the portlets, content templates, and stylesheets required to present content within the portal.
A portal often allows each user to select and reposition portlets within the overall presentation format.
A portal is not necessarily displayed on a desktop PC, but the same general concepts apply when designing wireless applications using XML content.