What happened is this:
On my website I put the WHDload.key so I could get it onto one of my Amigas. It was just in my private webspace, nobody should have seen it.
However, Google (or someone like it) found my publicised website for the Catweasel or something, and cut off the "Catweasel/" bit. This brought it back into my main personal directory which should never have been accesible, but Verio (the hosters) had by default set it to create browse info when you looked at index.html! This meant it picked up all the contents of that directory, including my WHDLoad.key, and Google indexed it!
I had no idea about this till someone pointed out to me that my personal webspace was visible. This is why I now have an index.html there which just says "Go away, nosey!".
I think what irked me most, though, is that the WHDLoad guys could have bothered to email me - they had my address - and asked me why it was available. The fact that they just made future versions not work with my (legally paid for) registration key, with no warnings or anything, not even a notification - that was rather shady and undeserved. I paid for something for future updates and they crippled it with no warning - not good. If it weren't for the fact that the last working version runs everything anyway, I'd be complaining more loudly, though.
That said, it still really is an excellent piece of software, and I don't regret buying it at all - even though I can't use the newer versions through no fault of my own.