There are a number of things that you still can't do on the web. This is the to-do-list to continue the convergence of desktop and web applications.
- Handle file types for opening - a file double clicked from the desktop should be able to open up a web application
- Handle saving back to the desktop - a file opened from the desktop should be able to save back to the desktop
- Better off line support - this is in the works but most apps still don't do this
- Embedding objects - I can't take a Yahoo table/chart and embed that in a gmail email.
- Desktop Installation & Integration - Web applications should be able to 'register' or 'install' to get a link in the start menu
- Hardware integration - web applications should be able to get hardware status and data such as GPS location, webcam, etc.
- Drag-in & Drag-out - Users shoudl be able to drag objects into web-pages to import or open a file and drag out to export a file or data
- Raw processor horsepower - As web-applications get richer and more complex they will need to harness the power of the desktop for photo editing, video editing and other advanced applications
- Optional chrome - The back-button may not make sense for every application. A calculator or post-it application should be able to be run from the desktop without the chrome. (not just widgets but real applications)
- Unified account system. (more than just OpenID but a complete & secure system that allows people to have a single & secure login across many locations)