Here's an associated question that archives everywhere are beginning to struggle with (though they should have begun struggling long ago). Many municipal records are being born digital these days, and records retention schedules telling us to keep a wide variety of materials permanently.
How would you store an ever-increasing amount of digital data indefinitely?
Given any method, memory diamond[1]. It's incredibly dense (25 grams of the stuff stores a bit over half a Yottabyte), and quite durable. If restricted to existing methods ... a metric fuckton of hard drives in raid arrays, outsourcing backups to cloud storage providers where possible, and investing as much money as possible in getting a way to use memory diamond worked out.
[1] Charles Stross describes it: "Memory diamond is quite simple: at any given position in the rigid carbon lattice, a carbon-12 followed by a carbon-13 means zero, and a carbon-13 followed by a carbon-12 means one. To rewrite a zero to a one, you swap the positions of the two atoms, and vice versa." See http://www.antipope.org/charlie/blog-static/2007/05/shaping_...
How would you store an ever-increasing amount of digital data indefinitely?