Jaanus Kase bragged about running four [different] Skypes in one box, and Jim Courtney asked how would someone come up with (and have the time for) doing this.

Well, there are several reasons I could come up with quickly (in no particular order).

• Testing. You may want to test the new versions of Skype (and/or Skype Extras) every now and then. On Windows, uninstalls are almost never complete and clean, so if you don’t like your machine’s registry and other places getting clogged with all sorts of leftovers of the stuff you’ve taken a look at. Furthermore, “scientifically” good tests must be done in controlled environment, and a system contaminated with random remnants of previously installed software would not exactly qualify.
• Features. Skype does not offer identical feature sets on Windows, Mac, and Linux. While the Windows is still the most-used desktop operating system worldwide, there is a growing number of people who prefer Mac OS X or Linux. So if you’re one of the “heretics” but still want to occasionally use the newest features that have only made it into Skype for Windows thus far, firing up a virtual machine with Windows on it would make sense.
• Hack value. Hey, it’s a freaking cool hack, isn’t it? 😉

As I do have to test new stuff, and as I don’t boot my computers into Windows (I’ve been on Ubuntu Linux for nearly two years, and see no reason to switch back — but that’s another story), I have a VMware Server and a bunch of (licensed) virtual OSes installed. So it takes me less than 5 minutes to unzip and boot into a “virgin” Windows XP or Vista without ever having to go through the entire re-installation of the operating system.

One thing I can not do (yet) is using Skype for Mac OS X on my Linux box. Apple’s licensing policy does not support running OS X on virtual hardware, and although several hackers claim they’ve got OS X to run in VMware on Linux, I’ve not taken the trouble.