Part 3 of the series coming soon - honest guv. Maybe today even. Anyway since it seems to be the season for challenges (or here or here) here is one I posed on Oracle-l in a rather meandering response to a question about scalability.

show me a serious stateless web app - i.e. one which really works with no persistence at all (the acid test is does it run unchanged with no loss of functionality on any browser with cookies disabled). I have yet to see one, seriously. I don't see how there could actually be one, you must interact with the user session in any serious application

The kicker of course is that if you can't do proper apps without state then you pretty much are going to be dependent on an RDBMS for any serious app.