DropBox , Apple iClound and now new cloud service
In Google Drive, you can create new documents, spreadsheets and presentations instantly. Work together at the same time, on the same doc, and see changes as they appear.
Google Drive tracks every change you make—so when you hit the save button, a new revision is saved
Google Drive is available for:
PC and Mac
iPhone and iPad (coming soon)
For more information visit: drive.google.com