It's referenced because this trojan is being spread by a porn site. The user visits the site and is then asked to download a new codec for Quicktime so they can view the site's videos. They download the .dmg file provided, mount it, run the installer, enter their password and then (if they're an admin user) they get a trojan instead of the codec that was advertised.
http://blogs.zdnet.com/security/?p=629

Unlike Windows though, this one certainly isn't going to leap out the browser at you. It requires a fair bit of active participation on the part of the user to get it installed.