Just a quick note: I've pretty much finished the permanent client side storage API I've been working on for O'Reilly. It uses a hidden Flash file, wrapped with a nice JavaScript API, to give AJAX applications the ability to store long term information.
I'll post a beta on Monday. It's all open source and opens up the possibility of creating some very interesting web-based applications that weren't easily possible before. I'll be using this in my AJAX consulting (including the history and bookmarking framework I created last week) if companies are interested.