The web is full of lists, including elements that we might not normally think of as lists, such as navigation. A navbar is essentially a list of links. Indeed, most navigational elements could be considered lists from a structural standpoint. In addition, Web text is peppered with lists because they are easy to scan. Users can form an overview and find information more quickly when it is presented in list format.
Visual users have cues that provide context for lists. Lists are often set off from surrounding text with spacing and indents. Items custom-arily appear one to a line, preceded by a bullet or number. These markers tell visual users where a list begins and ends, and delimit each item.
These visual attributes can be established without list markup. Spacing and indents can be accomplished using styles or table markup; numbers or bullets can be plain text. In fact, nonstandard lists—such as navigation bars, tabs, or breadcrumbs—are commonly coded using methods other than list markup. In these cases, visual users might not experience usability problems since list items are still visually distinguished. However, nonstructured lists are not as machine-friendly as structured lists, which means nonvisual users may encounter difficulties.
When lists are marked with list markup, nonvisual users have a way to identify them. Screen reader software can announce a list, tell the user how many items are in the list, and read off each list item individually. When lists are coded using other methods, however, this contextual information is not available to the user.
Providing context works best with simple lists. For visual users, it may be possible to effectively communicate multiple levels of information using indents and other visual formatting. For nonvisual users, nested lists may be disorienting.