GMail Drive creates a virtual filesystem on your Gmail account, allowing you to use Gmail as a storage medium.
GMail Drive creates a virtual filesystem on top of your Google Gmail account and enables you to store and retrieve files stored on your Gmail account directly from inside Windows Explorer.GMail Drive literally adds a new drive to your computer under the My Computer folder, where you can create new folders, copy and drag'n'drop files it.
Since Google began offering Gmail user's e-mail account, which includes storage space of 6000 megabytes, you have a lot of storage space but not much to fill it with. With GMail Drive you can easily copy files to a Google Mail account and retrieve them again.
When you create a new file using GMail Drive, it produces an e-mail and post to your account.E-mail appears in your normal Inbox folder, and the attached file as an e-mail. GMail Drive periodically checks your mail account (using the Gmail search function) to see if new files have arrived and to rebuild the directory structure. But basically GMail Drive acts as any other hard drive installed on your computer.