Zebra striping is a technique which is used to make data presented in a tabular format easier to read. When a table is zebra striped, alternating lines or rows are subtly shaded in different colors. The use of zebra striping in printed documents is fairly old, although it became especially widespread in the mid 20th century, and it is also common on the Internet and in electronic documents as well.
In a classic example of zebra striping, a bus table might be set up in columns which represent stops, with rows representing times. If the bus company wanted to highlight the times when buses stopped at particular locations, it might choose to zebra stripe vertically, allowing users to easily track the times that the bus stopped at a particular location. In this instance, the rows could be white or shaded, with the two options alternating.
There are several reasons why zebra striping is supposed to make a document easier to read. In the first place, the striping allows the user's eye to follow a line or a row all the way to the end with greater ease, acting like a sort of highlighter to draw the eye across or down the table. Striping also makes it more difficult to lose track of information, as the eye remembers whether it should be looking at a shaded or plain set of information. Zebra striping may also be easier on the eyes, by breaking a table up so that the information doesn't feel overwhelming.
You may hear zebra striping called candy striping or half shadowing, both references to the visual appearance of tables which have been zebra striped. Many data management programs which offer a tabling option also allow users to quickly and easily create zebra striping, choosing from a variety of shading and color options. Creating a zebra striped table online is a bit trickier, although there are various applications which perform this function.
There is some debate as to how useful zebra striping really is, but many people continue to zebra stripe documents because they assume that even a small improvement in readability is a good thing, and because people are familiar with zebra striping. From an aesthetic point of view, zebra striping also helps to break the document up visually, reducing the appearance of a huge block of material, which can be distracting and unpleasant to look at.