Here's something which may be of interest to some folk:-Disk Rot!
It's sad to think of so much classic software - especially home-grown one-off's - heading towards the bin. Stuff stored on data cassette tapes has faired just as badly (or worse) of course.
Luckily most of the good commercially produced stuff has already been saved as images and poked into various places around the 'net. And thankfully ROM-based stuff still marches on (and has been "imaged" as well)!