I came across this report today while working through my email backlog after my holiday. The whole report is available on the MS wesite : download
Vendors like Plumtree Software and Epicentric created the portal server market in the late 1990s by offering servers with technical features that just didn’t exist within firms’ existing IT infrastructure. Now those features — like UI abstraction, integration, workflow, and delegated administration — have been co-opted, improved, and embedded in general-purpose infrastructure platforms from vendors like IBM, BEA Systems, Oracle, and Microsoft. The standalone portal server market is gone, absorbed into infrastructure vendors’ app server platforms and emerging interaction platforms.
Interesting graph :