By default, web links are underlined, but a long-time design trend has been away from this and towards alternatives, such as bold or coloured links.
With accessibility again at the forefront of the web, Web Axe wrote an article, reminding readers of one of the big problems in ditching link underlines: “For accessibility, users with colour blindness or low vision may have trouble distinguishing links from regular text when the underline is missing. […] And for usability, it’s just easier to see the links and easier to scan them when they have underlines.”
The article added that exceptions could be made, but only for links in “visually explicit navigation bars [and] menus”, and text links designed to look like buttons.
Alastair Campbell, director at Bristol-based accessibility experts Nomensa, told .net that he essentially agreed with the article, but added that the motivation for retaining underlines is “just as much for people with cognitive or literacy issues”.
He explained that if you rely purely on colour for differentiating links, you need three: text, links and visited links, assuming the last of those is used. (He noted: “I’ve seen lots of regular people go in circles when they are not!”) The problem, according to Campbell, is visited link colours are usually less saturated than unvisited ones, which is appropriate, but also means they are “difficult to differentiate from the regular text, unless you use underlines”.
Campbell also said that although accessibility guidelines do allow for methods other than underlines (“for example, borders”), he reasoned that “the simple underline is generally the most elegant and understood method”.