I’m skeptical Team17 is still selling software as claimed in this 2010 article, as their website reads “© 2002 Team 17” and purchase links end in a 404 error!
Still, a good article, even if the idea that users don’t always know what they really want isn’t so new.
Edit: somehow I was on their old site. http://worms.team17.com/ - odd they let that subdomain stagnate!