IBM is citing an IDC study that posits WebSphere as the marketshare leader among enterprise portals. That might be true (IDC's marketshare studies enjoy a decent reputation)...but I doubt it. I think all these studies are inherently flawed because people have different ideas about what terms like "portal" really means. For example, IBM (like some competitors) uses its portal product as the presentation and interaction layer for a variety of middleware applications. Architecturally, this makes sense, but a WebSphere implementation doth not always an enterprise portal make. Also, all the major infrastructure players -- IBM, Oracle, SAP, and Microsoft -- have been known to give out portal software like candy, and I suspect the market includes a statistically signficant number of unused portal seat licenses. So all we can firmly conclude is that IBM is an important player in the enterprise portal space. But you already knew that.