One of the primary tools in the area of digital preservation is LOCKSS, which stands for “Lots of Copies Keeps Stuff Safe.” It works similarly to a mirror system: your library saves whatever it wants to save to a computer, and that data is backed up on computers all over the world, on the computers of other participating instititutions. If there is any difference, the LOCKSS software can repair any difference.
Without really realizing, I’ve been doing the same thing. I’ve been using Dropbox on my laptop and on my desktop. I’ve been saving all of my job stuff, class stuff, and masters paper stuff in my Dropbox folder; this is saved on my local computer, to the Dropbox servers, and then to my desktop when I turn that on. Its a good measure for personal data backups, but I don’t know if the LOCKSS program can be sustainable over the long term. To be a good participant in the system, you would need enough server space for all of your own data, and then a massive amount of extra space to provide backups for other insitutions. The point of having the data at multiple places is in case of a regional disaster, like an earthquake or hurricane. But will institutions be willing to give up this much server space? We shall see.