Dropbox saved my ass when my computer completely fried (I tried installing Windows on Boot Camp using a Dell install disc and my computer just refused to turn on). About 6 years' worth of essay drafts, stories, and poetry all got saved and backed up instantly - despite the fact that I'd deleted those stories from Dropbox months ago! I'd moved them to my computer from Dropbox and deleted them, but it saved it in my history.<p>It's not one of my most-used sites, since I rarely have need for it, but I wish I needed it more, because every time I use it I'm blown away by how easy it makes things.