Dropbox is a Web-based file hosting
service operated by Dropbox, Inc. that uses cloud storage to enable users to
store and share files and folders with others across the Internet using file
synchronization. It was founded in 2007 by MIT graduates Drew Houston and Arash
Ferdowsi as a Y Combinator startup.
The web link is: www.dropbox.com
If you want to Main page of DropBox,
you will se a tutorial video about how use it.