This may seem a little... out there, but have any studies been conducted about the psychological or even physical aspects of viewing a web page?
For example, psychologically, what makes a good or bad first impression? What the user is most likely to respond to and most likely to ignore? Physically, where do the user's eyes naturally gravitate to when first viewing a web page?
Things like that which involve how a user thinks and behaves regarding the look & feel of a website.
There exists another question, which answers some of these, but it focuses on loading times.
My biggest concern is the look & feel -- how do the users view the page? What kinds of things are attractive and keep their attention? Do people really like glossy social media icons everywhere? What kinds of features will make a user likely to leave?