1. A system to support a federated portal, comprising: one or more processors; a plurality of producer web applications that host a plurality of portlet applications on a plurality of web servers, wherein each said producer web application is deployed on a separate web server in the plurality of web servers, and each said producer web application is a container web application that hosts one or more said portlet applications, wherein each said portlet application is deployed and maintained separately; a consumer web application, on said one or more processors, adapted to collect and present available portlet applications in the plurality of portlet applications hosted on the plurality of web servers and offer the available portlet applications as a unified portal to end users; wherein the consumer web application operates to establish contact with each said producer web application, and ask each said producer web application for available portlet applications hosted on said producer web application, and wherein each said producer web application operates to define a property set that allows end users to input values for the property set; map the consumer web application to one particular role in a role set which includes a plurality of roles; check for portlet applications that are available among the one or more portlet applications on said producer web application based on the particular role, and response to the consumer web application with a message that describes the available portlet applications hosted in the producer web application.