Google has just announced their own operating system "Chrome OS" which will be, as the name suggests, is a project that branches off from their recent browser Chrome according to their blog. It will run with a Linux kernel at its core and the goals are for it to be lightweight, safer and faster to boot up than windows. It also appears most of the free software will be offered as web applications that can only be run via the internet.
That's all good but I think the biggest obstacle will be how much backing they'll have from the major hardware and software manufacturers. If there's a lot of compatibility problems, the casual user will probably end up sticking with Windows anyway - Especially gamers and graphic artists.
It will also have to be easy to install new programs too whereas in Linux distributions, it's a little more complex since most of the time you have to compile the source code yourself before you can use them.
Either way, it will be interesting if this Linux based project will prove to be more popular than other distros such as Ubuntu.