Desktop two dot com is another application in a long list of online OS replacements competing to get a piece of this new market. The idea is that instead of your native OS like Windows Vista, Mac OSX or Linux, you’d run Desktoptwo, which is a purely online operating system that runs using Flash and Java.
The pros to this setup are a truly mobile and modular operating environment. Accessible from any web connected PC. The downsides or cons to online operating systems are the fact that they currently depend on an Internet connection (something that isn’t quite everyone yet) and also that it requires an existing operating system to run.
I’m going to repeat that last con so it sets in a little, “you need an existing operating system to run the online operating system”. This is a big con, and until PC’s can be built and deployed with a bios/light OS, online operating systems will remain a niche product reserved for uber geeks and specific users who require an online OS.