This is a good way of passing from the typical 2Gb of storage that they offer for free onto a max of 8Gb.
Right now, they are offering to double this offer from 250Mb to 500Mb for students. The only catch is that this only works with student emails that end as a .edu domain extension. The good news is that previous referrals are also accounted in double, no need to ask anyone else to also register.
I've tested with my email from Carneggie Mellon and this doubled the available online storage to 16Gb on the spot.
I'm not sure how long it will last, but if you use dropbox and have a student email with .edu then go right ahead to activate this neat option at the following link: http://db.tt/edu
