I'm writing a chapter on the design of portals for a human factors handbook (Handbook of Human Factors in Web Design, 2nd Ed.). I'm doing my best to dig up the current state of the art in this, but have come up with little formalized content. There was a brief IxDA discussion thread about this in May of 2008, referring to an excellent series of articles and related IxDA conference presentation on a portal design framework by Joe Lamantia. And there are the reports by the Neilsen Norman Group resulting from each year's Intranet Design Annual competition.
Are there any other pearls I need to make sure I pay attention to?