One of the things that I dislike about my current backup setup which uses JungleDisk and Amazon's S3 is that I pay for the amount of stuff that I back up. That math makes sense: I don't pay very much - but it's not free. Leaving a file on my hard drive is free (basically).
So when I scanned a 5 MegaByte image that I later used Optical Character Recognition to extract the text out of, I wondered if I actually needed to keep the file. 5MB isn't trivial.
How much does it cost me to store that file, say for 7 years?
7 years * 12 months = 84 months * $0.15 / GB * 5 MB / 1000 GB = $0.063
About 6 cents for 7 years. So if I have 1000 photos all that size (which my photos are not), that will cost my $63 to store for 7 years. Seems cheap.
That's the economics of large-scale at work. Amazon buys thousands of servers and everyone uses a little-bitty piece. They figure out how much that piece costs (it costs them $0.12 so they charge me $0.15) and we share the cost savings.
