If I buy a CD and listen to it at home that is legal. If my wife listens to it, that is legal. If I invite all our neighbours round that is legal. But should I make a copy for my wife to listen to on her mp3 player, then that is illegal.
If I use a piece of legally acquired commercial software on my PC then that is legal. If I backup the software because I wish to ensure that in event of a failure I can quickly restore the software that I have paid for, this is illegal. Should I back up data created by that software, if it uses a format copyrighted by the software owner, then this is illegal.
My source for these statements - the UK Intellectual Property Office following a recent High Court judgement.
This unbelievable state of affairs arises from the continuance of 19th C legislation designed to protect authors of printed books and the inability of our legislators to understand the nature of digital goods. It is comparable to the law (repealed in 1896) requiring a man with a red flag to walk in front of a motor vehicle and deserves the profound contempt of all ordinary law-abiding citizens. No commercial interests whatsoever are harmed if my wife listens to something on her mp3 player that she can hear on the cd player at home. No commercial interests are harmed if I back up, for my own protection only, software or the data created by that software.
It is ludicrous that millions of ordinary people and thousands of businesses, charities, and almost certainly many departments of HMG are, theoretically, law-breakers. The High Court judges involved in this decision should be de-wigged and made to live for a few years like the rest of us in the real world.