I don't see how most computer screens - even the large widescreen ones are a problem when reading webpages. I sort of like scrolling... It would be weird for me to read from the top of the screen, move down to the middle and then make my way to the bottom. What I usually do when reading is keep my eyes in a relatively fixed position and I just scroll down very slowly. This thing is pretty cool, but it might be a little annoying to have tabs on the side just to save 10-20 pixels of vertical screen.

And while I don't find it difficult to click on tabs (keyboard shortcuts!) I really like the idea of having the url inside tabs - adding that firefox/chrome and then getting rid of the url bar would be pretty cool.