<http://schema.org/description>
"Insanely popular folder synchronization service Dropbox has doubled the amount of free space you get from referring another user to the service. You now get 500MB instead of 250MB of ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/apps/2012/04/04/dropbox-doubles-the-space-that-you-get-from-referrals-to-500mb-per-signup/>