Above The Fold

http://www.youtube.com/watch?v=HT1xMKHCae8

The RoboMail Channel

Above-the-fold is the portion of an email page that you first see without scrolling. Above-the-fold is generally the most desirable location of content in an email because it is the most readily visible. With the increase of people using mobile devices to view email and wide screen formatted monitors, above-the-fold is getting harder to determine.

NOTE: Using external CSS sheets to render the email is the most effective way of rendering the content above the fold.

"Above the fold" is a graphic design concept that refers to the location of an important news story or a visually appealing photograph on the upper half of the front page of a newspaper. Most papers are delivered and displayed to customers folded up, meaning that only the top half of the front page is visible. Thus, an item that is "above the fold" may be one that the editors feel will entice people to buy the paper. Alternatively, it reflects a decision, on the part of the editors, that the article is one of the day's most important. By extension, the space above the fold is also preferred by advertisers, since it is the most prominent and visible even when the newspaper is on stands.

The term can be used more generally to refer to anything that is prominently displayed or of highest priority.

This term has been extended and used in web development to refer the portions of a webpage that can be visible without scrolling. However, some have suggested that this term is inaccurate as screen sizes vary greatly between users, especially in an era where websites are viewed with mobile devices as much as home computers. From: http://en.wikipedia.org/wiki/Above_the_fold

Screen Resolution and Page Layout:
Optimize : for WIDE SCREEN format, (16:9 and 16:10) it's probably about 80% of your viewers can see that.
Liquid: use a liquid layout that can stretch the entire length of the preview pane.