OOW2K6: The presentations we can't see
One category of presentations which is not available are any Oracle presentations alluding to features which may or may not be in the next release of Oracle. It would seem the legalistic get-out at the start of each presentation covers the session itself but not subsequent publication of the slides anywhere else. So if like me you missed a presentation or just didn't take adequate notes, well, you'll know better next time.
Since posting this I have tried to download some other presentations. For some reason PowerPoint will not open Oracle-sourced presentations. I don't think it is due to corruption in the content management system as I could open a non-Oracle PPT file. It may be a trojan macro embedded in the template by Oracle's legal department ;) Anyway, this is another good reason to convert presentations to PDF. I've been using Primo PDF, as recently recommended by Tom Kyte, and it really does the business.