This is a new compression that is opened by a program called winzix (http://www.winzix.com). Apparently, this is a bit of a scam. See, whoever made winzix did so fairly recently, and there's a bit of adware attached to it from some company so that they can make money off of it. Wikipedia has a good run down on the opt-in adware or spyware component it installs (http://en.wikipedia.org/wiki/Winzix ) Opt-in means the features of the software are fully disclosed in the EULA.
"In any case, now the creator has someone distributing torrents of TV shows and whatnot compressed as a .zix inside a .rar, along with instructions to download winzix to "view your file."
So you can see how this is an elaborate ploy: torrents are distrbuted without any mention of the .zix format, once you spend hours downloading them you find out that you need winzix to open them, and the fact that you've already spent all of this effort obtaining the file leads you to install winzix, even though you know there is adware attached which you do not want and is bad for your computer. This is how the creator gets you to install it's adware, and this is how he makes money from his sponsor."