I wish there was a PC version of this, too, just so I could mess with all the people checking their Facebook in class.
There's nothing more distracting. Could they not at least have the decency to sit at the back of the class? Because when they're on Facebook and they're on Tumblr, and images of parties and flashy .gifs are flickering in front of you, you get distracted. You may not stare at the screen over their shoulder, but you'll look over and miss a slide or a helpful tip from the prof.
As much as I'm for the use of technology in school, especially for assignments and checking grades, taking good old-fashioned notes is still the best way to go. Until people are responsible enough to turn off the internet while they're in class (Microsoft Word doesn't require internet access!), then I don't think taking a laptop/Macbook to class is a great idea. Do it if you promise to leave the internet alone. But if you're going to check Facebook and browse Tumblr, sit at the back. The very back.