Several possible ways to use a CMS for or within a portal come to mind. The first and most important question is: who gets a request first - CMS or application server? And who assembles the results into the firnal form? And how is the content coming from the application server represented in the CMS (tooling etc.)? Does the application server deliver only presentation-less results, e.g XML streams? Or do both, CMS and application server extract results in XML and then somebody assembles the results to a personalized page? This would circumvent the advanced caching capabilities of the CMS.