The job of designers is very difficult… I don’t say that because I am a designer, but it’s a fact proven by several statistics. People judge the quality of a website in just few seconds and a second impression is something absent on Internet. In conclusion, a website must be eye-catching else, it would be nothing more than a big failure.
Having full control over the fold (the part of the layout that is visible without scrolling) is vital in making a website. The experts divided the layouts in few components so you may study more exactly how each pixel affects the overall appreciation over a website. The classifications are anyway, not scientifically or very rigorous, these are made for a better study, therefore don’t spend your resources thinking how to created new classifications.