This extension allows you to use your Gmail Space (2 GB) for file storage. It acts as a remote machine. You can transfer files between your hard drive and gmail. Your gmail account looks like a FTP host and you can upload and download your files. After you install, you get an option called "GSpace" in your "tools" menu clicking on which opens the window for transfer of folders/files. You need latest firefox version 1.5 to install the extension.