The Key
There are few software products whose principal selling point creates quite such an interesting problem for the sales department.
The Key was a clever little utility designed to copy and back up Spectrum programs. For &£5.95, KeySoft would put in your hands a program capable of copying software far larger than itself, despite running on the humble 16K Spectrum.
And then, apparently without consulting the marketing department, it could copy itself.
This is rather like selling a key-cutting machine which includes instructions for cutting another key-cutting machine.
Technically brilliant. Commercially… adventurous.
The irony becomes even better when you read the instructions. KeySoft quite reasonably reminds users that copies should be made for personal backup purposes, while simultaneously protecting The Key itself with copyright.
In other words:
“Copy software responsibly. And whatever you do, don't copy the thing we just sold you to copy software.”
Yet this wasn't a novelty program. There are multiple surviving versions, including a headerless variant and a Spanish release, suggesting that The Key was developed and distributed as a serious product.
And at £5.95, it was hardly an extravagant purchase.
The only question is whether KeySoft's customers were sufficiently law-abiding to buy The Key once — or sufficiently enthusiastic about its abilities to ensure that they never needed to buy it again.
Verdict
A remarkably capable piece of early-80s software whose biggest technical achievement may also have been its most awkward business feature.