A long time ago (read: about 4 years), in a galaxy far, far away (read: Silicon Valley), a guy named Drew Houston started a little company called Dropbox. After securing seed funding from Y Combinator, Dropbox officially launched in 2008 at the TechCrunch50. To say nothing of the complexities of implementation, the idea was simple: put your files in one place, access them anywhere. And apparently, the idea was also a really good one: as of October last year, Dropbox had over 50 million users, doubling from a figure of 25 million in April.
Today, Dropbox is without a doubt the preferred method of sharing and storing repositories of files (as opposed to mere individual ones) on the web.