toolbar/Firefox extension
You have a nice suite of online applications. A toolbar or especially a Firefox extension would really enhance the usability of your services. You could include a sidebar view with search, previews and links to my various files and services. The toolbar could have a button for each service or perhaps customized buttons to link to a particular file or user. The toolbar could have an option to auto-signin. The reason I particularly favor Firefox extensions is that they are mostly cross-platform: ie the same extension will generally work in Firefox for Windows, Mac, or Linux. That is useful to me because I use all three platforms, and I am able to create a fairly seamless experience using Firefox and several key extensions.
brent.hopkins