Why do people sell scripts?

[AceInfinity]

I have a couple of spammer javascript facebook scripts that if executed by the facebook user will post a link on a random selection of user id's from your friends list, message them, and talk to a selection of people in your chatbox with a posted link then it removes all that recent activity off your wall so it's harder to track and delete afterwards. There's been tons of scripts that i've traced from facebook. I don't even use facebook though.

Selling something like that he might not realized the potential for it, seeing as how anything new and innovative done with facebook gets recognized fairly easy.