Dropbox is a popular online file storage app. Imagine it as a type of online USB drive, which you can access anywhere in the world as long as you have a computer and internet connection. If you have a Dropbox account and also use Moodle, you will be glad to know that in Moodle 2.x you can connect the two together and use Dropbox as a Moodle file repository.
http://elearning.3rdwavemedia.com/blog/how-to-use-dropbox-as-a-moodle-file-repository/605/