Wubi is a simple and easy to way to try out Linux. It installs Linux like any other program on your Windows-based computer, requiring no confusing partitioning or dual-booting nastiness. Once installed, it keeps all of its own files inside its folder and basically acts like a full-blown Ubuntu installation. You can see what Linux is all about without having to be a computer-guru to set it up and see if you like it.
It’s a great idea for those too afraid to give Linux a shot.
My only concern as a technical user is: would users new to Linux think of Linux as an application on their Windows machine and not realize that it can replace Windows on their computer due to the way Wubi is presented?
Time will tell of course, but for now newbies can rejoice!