I'm just curious as this is a new phenomenon compared to the time many years ago that I was a student. I have no feelings positively or negatively about it.
I think it started in earnest about 5-6 years ago, with some fields more than others. My friends were in MBA grad school at the time and it was common in those classes. When I was getting my PhD, grad students would rarely do it (but classes are small, making this sort of thing awkward), but when I taught undergrads a few would do it. Most of the big lecture halls built in the early 2000s (when the thing to do was to build lecture halls with long tables and built-in chairs) had ethernet ports, and of course now classrooms are usually wi-fi equipped.
I experienced more of the reverse backlash. When I was an intern, I had a staff psychologist reprimand me for using my iPhone during a seminar (to look up research articles related to the topic at hand to see what was known about a related issue). I think she thought I was playing video games or something.
I'd think a tablet would be much more discrete than a notebook or netbook, but I think it's become fairly acceptable in big lecture classes to use notebooks now, as long as one is careful not to be disruptive. I think it's important not to assume students are trying to be a nuisance (as an instructor) but also be firm in expecting that they not distract others. (EDIT: on this aside, when I taught at Florida, it was expected that most classes use some kind of attendance-driven mechanism to contribute to grading, and if I didn't want to take attendance of 75 students, which I found to be a pain, I was expected to at least do something like give pop quizzes. I thought this was all a bit of a nuisance. At Michigan it was fair game to never go to class, if you learned the material anyways. I once got an A+ in a basic electrical engineering class that I stopped going to after a couple of weeks.

).
Back on topic, I have a 1005PE which is just under two years old. I don't feel like a lot happened since then, up to recently the interest in Android-based netbooks like the Transformer Prime. This is the second EeePC I owned; the original was a fun toy that mostly served its purpose of having something cheap to learn how Linux works on it, but I really actually quite like this one. And the battery life
is rather phenomenal. If / when I replace it, I'm tempted to get an MBA, in part because I haven't bought a Mac in years. I'm probably with you -- if I got the Transformer Prime or something else that didn't run Windows or OS X, I guess I'd start asking why not just an iPad or something like that.