Difference between Windows Sharepoint Services and Sharepoint Portal Server 2003

I ran across a Microsoft Knowledge Base article the other day that has a good comparison of the features in Windows Sharepoint Services and Sharepoint Portal Server 2003. This information exists in other places, but this is a nice concise summary. It also has links to white papers, etc. Since the Portal Server is built on top of WSS, it has all the WSS features, plus. My favorite plus feature is the My Site feature - basically everyone on the Portal Server site can have their own personal site, as well.