I use a macbook air as my only computer and I do not have an external display. This means that my screen has a maximum resolution of 1440 x 900.
For those of you with multiple monitor setups you might think it is odd but it works for me and forces me to concentrate on the task at hand (or it would if I didn't have a tablet and phone as well).
We all know that size really does matter no matter what some nice people might tell you but does length matter as well? There is no point in writing great content if nobody will read it so length does matter - line length that is - what else did you think I was talking about.
The web was meant to be read, not squished.
This isn't the way to test a responsive design.