Gmail Drive Shell Extension is a genius tool for Gmail users. Well, actually for users who use gmail a lot. Not every user. The application logs in to your gmail account and keeps a record of the file attachments that your e-mails have. Thus, it is able to create a sort of "virtual" folder on your computer, where all your e-mail attachments look like regular files. And you can copy, delete, cut, and duplicate them in any way you want. You can also copy files to that directory. When you do so, the application will automatically send yourself an e-mail with the file you are copying as an attachment. Using the "search" function of Gmail, the application will then be able to find the file and show it on the virtual directory. With several gigabytes to use on your Gmail account, this proves extremely handy for people who need to upload files somewhere for retrieval later on. However, I think using this application goes against the terms of services that you accepted when signing up for Gmail, so use at your own discretion.