If you've ever needed your computer fixed by someone who knew computers better than you, you've certainly found yourself remarking at one thing in particular: Their keyboard usage. Strictly speaking, I believe there's a direct correlation to skill with a computer, and frequency of keyboard use over mouse use. Even if you consider yourself an advanced power user, chances are that if you come across someone who's better at a computer than you they use the keyboard in places you'd resort to the mouse. Of course this is a one way correlation, and a general rule of thumb with your typical exceptions. That is: If you use the keyboard all the time it doesn't guarantee that you'll be an amazing computer user. But if you're an amazing computer user, chances are you use the keyboard more than those who are less amazing.As far as the three major operating systems go - major in terms of awareness, rather than usage - I've noticed some glaring differences with how much the keyboard is used and a term I can only lovingly describe as 'Geek Quotient.' This is no claim as to which operating system is better, only what I've come to learn in my own encounters with the operating systems, as well as observing the true champions of each.I'll start with Linux. That operating system with more flavors than Baskin Robins - for a full list, see Wikipedia . While there are many different forms of Linux, some more UI based than others, I'll speak of them all rather loosely, by just referring to Linux, and for a simple reason: The harder your core, the less you care for the shiny gloss that people load on top of the basic stuff. That is, the purists who write their code/love poems in VIM, and surf the net using Lynx. If you're one of these purists, chances are your hands almost never leave the keyboard - particularly because just to get the mouse working in VIM requires loading additional plugins. And while it's certainly not beyond your ability, by the time you're skilled enough to know how to load the right drivers, and include the right plugins, you're far more efficient with the keyboard you don't care anymore. These types of users will build powerful machines, maxing our their RAM slots, having the latest and best processing power and video cards, and then put it to good use by running programs that already ran at lightning speed before Ram was measured in Megs. If you can get started with Linux, and don't get frustrated with it, rest assured you'll soon get excited about fixing bugs in your own build, and brag about the extra room on your desk ever since you got rid of your mouse.Windows is a much more linear growth. As most of the world uses Windows with varying degress of complexity, your savvyness is often directly related to how much you use the keyboard. The examples are plenty. Compare yourself to your parents - who likely take their time moving the mouse from button to button. Peculiarly, not only will they take the mouse to any point of the button, but they almost insist on placing it at the center of the button, as though they are applying a greater force to ensure the depression will be detected. Chances are if you're familiar with the tab button, watching someone mouse to each button is a frustrating experience. If you're an alt+tabber, shift+tabber, the experience is all the more excruciating. A lot is possible with Windows in terms of keyboard shortcuts, but it maintains mousability the entire length of the way. You can get geeky, but it takes a lot more keyboard use than your typical Linux user.So Mac OS - why the double curve? A lot has to do with Mac's interface. Macs are - for the most part - user interface machines. They're all about interactability. They're gooey, squishy, glowey. Some how the Mac people have managed to translate a texture to the mouse, so much so that it's difficult to take your hand off that mouse. Everything is a click away. Where Linux has the shell, allowing you to type out your commands and length, and Windows has the start menu - with keyboards that have quick access Windows buttons, allowing users to use either mouse or keyboard, Mac OS is a clicking machine. Hardware-wise, Macs reflect this same philosophy. Everything is packed away, deep inside with no visible seams. All you need to get it going is a single power button.But then again, let's not forget that Mac OS is built on top of Unix. The not-so-free inspiration of Linux. And while it's very clickable, underneath it all it has the same stripped away feeling of console. And once a Mac user unlocks the Unix portion of a Mac they're comparable to a Linux user - though, it does take some time to get there. And at that point, they may very well switch to Linux anyway.There's a spot where the three lines converge and then diverge, as they intersect and then go their separate ways. It is here that three operating systems take their own course, where their philosophies become evident. This spot is also, what I'd call the UI Sweet Spot. Why? If you're someone who makes your living out of developign User Interfaces, you'll see this is a spot that works for all types of users. Keyboarders may still keyboard, mousers may still mouse, but it's intuitive to all users - not demanding anyone to step out of their comfort zone. Of course, because the sweet spot is quite obviously not at the origin - which is why, if you extend that box to incorporate the origin, you've got a universally approachable UI.And that is the UI dreams are made of.