Layout and page design for web sites is somewhat restrictive compared to layout and design of print material. The reasons are various sizes and resolution settings of the computer monitor, tablet or smartphone. We use the term “above the fold”, which is the section of a web page that is visible without scrolling. I call it the PRIME “real estate” of a page.
On a desktop the fold varies depending on the resolution settings on a user’s monitor. At lowest settings (i.e. 640×480) the fold is relatively high on the page. At higher settings (i.e. 1280×1024) the fold extends much further down the page. Decisions concerning what goes above or below the fold are often made based on a minimum targeted resolution. On a tablet or smartphone it is almost inevitable that one will scroll, however, one should consider what is most important to appear at first sight.
For maximum exposure of the most important items or messages a placement that is high on the page, assumes that it will be viewed and clicked or tapped more often. That’s why you will typically find the navigation at the top of the page, always ‘above the fold’.
Here is an example:
If you are placing a banner ad above the structure containing the main content, then the ad can be viewed before the main content loads. When your ad is allowed to pre-load, being above the fold may be favorable in terms of generating awareness.
However, if a banner ad is being served from an overworked server, the image may not render before the user scrolls down the page. In this case being above the fold may be unfavorable. So make sure that the server is running smoothly before you “invest in real estate”.