This is very relevant, and perhaps deserves a submission of its own:

http://news.bbc.co.uk/2/hi/technology/2534391.stm

"""But the snapshot of in the UK in the mid-1980s was stored on two virtually indestructible interactive video discs which could not be read by today's computers. """

I can't find the back story now, but if they weren't able to source a working laser disk reader from a member of the public (which IIRC took quite a bit of effort to find), then accessing this data - digitized in the early 1980s - would have cost a fortune.

The inspiration for this project, the 900-year-old Domesday Book, is just as readable today as it was in 1980 (and in 1200 or so). The ability to read data with one's eyes should not be underestimated.