I'm strangely relieved to read this post and all the comments to it, and see I'm not the only one. I can force myself to work or research for two or three grueling hours, and then I sit down to take a "quick break" online, and I look up and three more hours have flown by. WTF?

If it helps, your post did inspire me to get offline, spend two hours reading The New Yorker and, okay, take a long nap, which I tell myself was much better for my eyes than staring at the screen. It really is an odd adjustment: reading on paper vs. reading on a screen. It does affect my brain in different ways. This is why I do most of my research/dissertation writing in longhand!