A web page, in its basic form, is simply a communication channel. It organizes and displays information to a visitor. These visitors do not read websites like a book; they scan information as if given a flyer on the street. For more details on this check the article "The First Three Seconds: How Users Are Lost." In a world of users scanning websites, the positioning of information is paramount. Back in 1885, a German psychologist named Hermann Ebbinghaus coined the phrase "serial position effect" to explain how the placement of information affects an individual's ability to recall it.
The serial position effect is broken down into two areas: Recency and Primacy. The recency effect states that individuals will recall additional information about more recent data because it is still in short-term memory. For example, if a user is asked to recall a list of words just spoken/read, the user generally starts with the bottom of the list and will remember more from that area. After recalling the last few items, the Primary effect takes over. In this effect, a user recalls the first few items in a list as the brain has committed them to long-term memory. This was an important discovery because it highlighted the subconscious importance and the subtle ignorance placed on information.
Armed with this knowledge, any programmer can make a difference in basic web design, but how? It's important to review the overall visual hierarchy of a website. Information should be broken down into smaller, consumable areas. Large sections of data can be easily separated with illustrations, headings, or simply a more formal layout such as a list. Breaking out information helps with information recall and it is more visually appealing. This is where Hick's Law regarding smaller lists becomes important. Read more here. Don't forget to review the overall layout again after a set of changes are made. Sometimes small decisions can start to encroach on the larger hierarchy of a web page.
Even though Hermann Ebbinghaus's findings are more than 100 years old, they have never rung more true. The information age has brought along with it a level of saturation that is unprecedented in human history. Having a better understanding of a visitor's psychology allows for better, smarter design. The Internet is a very large place and it can be difficult to make an impact. It's all about making memorable, "sticky" content that drives return visits or creates happy visitors.