In an obvious attempt to entice DropBox users to switch to Cloud storage service OneDriveThe Microsoft gives all Dropbox customers 100GB free storage space for one year.
To get the GB donations, visit this page to sign in to OneDrive and then verify it account your Dropbox.
The offer appears to be working globally.
Please note that OneDrive already offers 15GB free storage, 2GB in addition to Dropbox.