|Today, virtual appliances are becoming a de-facto means of software distribution and have spawned a new type of business — the virtual appliance vendor.
Along with software vendors and virtualization software companies, appliance vendors are putting in the extra effort to streamline the distros that power the apps. So, for example, Bugzilla, the popular bug tracking app, is available as a 2.4MB download tarball from Mozilla, as well as a 150MB appliance from appliance vendor Jumpbox. Mathematically, this is 62.6 times the size of the app, but in 150MB you’re also getting an operating system, stripped to the bone and optimized to run only that particular app.
Mayank Sharma, A virtual appliance primer
Am still trying to figure out why we won’t be using virtual appliances for just about everything and how the distribution model fits in with SaaS.