Just over four years ago, Apple came out with the Mighty Mouse, its now-standard multi-button mouse with a scroll ball. I talked about the mouse as a canonical example of a device that is "easy to use," but its evolution shows that the definition of "easy to use" changes a lot over time. The release of the Magic Mouse shows the same pattern: it's a device that Apple is presenting as easy to use (and at the same time revolutionary), but its ease of use depends not on the permanent revolutionary genius of Steve & Co., but on the changing repertoire of user skills.
As I explained in a 2005 post, when it first appeared in the early 1980s,
the mouse was a total novelty, and anything with more than one button required users to think and make decisions. In contrast, in an age of Game Boy, Playstation, Treo, Blackberry, and the cell phone (not to mention multibutton mice on Wintel machines), kids can look at a device with four buttons and a scroll ball and think, "Hey, that's easy to use." To me, the best indicator of just how far the goal-posts that define ease of use have moved is the now-pervasive use of thumb buttons on mice. Doug Engelbart wanted to put more than three buttons on his mouse, but couldn't figure out how; apparently they didn't think of putting them on the side of the mouse, under the thumb.
What this tells us is that while the concept of "ease of use" is wonderful, and to be encouraged at all times, just what constitutes ease of use will change over time. It's not some unchanging Platonic ideal; it varies and evolves over time, and is defined by a community's exposure to earlier technologies, levels of mechanical or physical skill, and a bunch of other factors.
The Magic Mouse represents another example of practices that now define "easy to use" but were once obscure. The top surface of the mouse is one big multitouch area, like an iPhone or iPod Touch: there's no physical button, and instead the surface identifies certain zones as the equivalent of a left button, right button, etc.. You can also do two-fingered swiping.
Before the appearance of the iPhone and other devices with haptic interfaces, the physical vocabulary of swiping, of having zones on a device that changed their function depending on what program was being used or what mode you're in, would have been alien and confusing. Now, no longer. It's another section in the secret history of physical skill that's part of the history of computing (and which we still don't pay enough attention to).