I followed a link entitled Is Linux the greatest threat to Windows Vista? The author makes some interesting comments, but falls into the typical trap of assuming that since the Linux architecture is superior to Windows that Linux must automatically succeed. Sadly, nothing could be farther than the truth.
While I want to agree with the author here, honesty compels me to disagree. Too many people are propagating FUD about Linux, particularly about it not being ready for prime time. Whenever a user has to open a terminal session in order to fix something, they cry out that Linux Just Isn't Ready. Whenever anything doesn't "just work" the way they demand, they cry out that Linux Just Isn't Ready. Whenever their favorite software package isn't offered for Linux, they cry out that Linux Just Isn't Ready.
Microsoft has done an excellent job of seeding the community with FUD, and the Linux community has a lot of work ahead of it in order to counter that. You and I may know that there's very little difference in terms of the amount of work necessary to get Windows and Linux up and running, but our opinion is in the minority.
There is no such thing as the Perfect operating system. No Linux distribution is 100% glitch-free or guaranteed to work 100% for users determined to be ignorant. Windows, even XP at its most stable, requires a great deal of tweaking and installing before users can do what they want with it, but since much of that is done for them when they buy it from the shop they carry that expectation over to Linux when they try it. That's why it's so vitally important to support vendor-installed Linux initiatives from companies like Dell, HP and Lenovo. The more people come to learn that Linux Just Works the way they've come to expect from Windows, the more Linux will gain market share.