Have you considered file storage in the cloud? I note that some services like chart.ly are becoming very popular for sharing compelling visuals. On a similar note, are you sure you want to use the Drawing1.xml as the default bookmark text? I don't know if that will help me remember the site a year from now. But diagram.ly/myusername/mydrawingname would be cool.
Yeah, working on direct access to Google Docs accounts so people can save/load using that. Same for Dropbox, Jungle Disk,etc, will come later. Google Docs proving a bit tricker than we hoped, but we'll get there.
Don't really want to get into us storing the diagrams since we don't want to charge for this. But maybe we could look at storing just the raw XML, that would be pretty cheap on Amazon, even for a lot of diagrams.
Good point with the bookmarking, we want the tab to show the drawing name, but that BM isn't helpful. We'll look it that.