This doesn’t sound ethical to me but that’s not going to stop people doing it.
It’s a news form of marketing software that’s geared to people using file sharing software like KaZaa.
It works like this:
A software vendor uploads multiple copies of his product to a file sharing network. He labels the product in such a way that it looks like a pirate copy of his software. He describes the product so that it looks really attractive. He does this because he actually wants people to download the "pirate" copy.
That’s because it’s more than a pirate copy. It also includes an additional module not found in the original product: a trojan horse.