Dropbox the popular folder synchronization service has doubled the amount of free space.You can get this extra space by referral program of dropbox.Referring another user to the service. You now get 500MB instead of 250MB of extra space, topping out at 16GB of free space.
Dropbox says that it rolled out the referral program after it noticed Dropbox spreading the most through word of mouth from current users. It started out giving 250MB, then doubled it for students. Now it is expanding the ‘double space’ program to all of its users.
Dropbox has instructions available on its site for how to share referral links with your friends and family in order to earn yourself more space.