Reviewing the rules for links we find:
- Links should be obvious
- Ensure good contrast between link text and background
- Link from key words and phrases
- Link targets should be predictable
- Use a different color for visited and unvisited links.
As for color, achieving a a balance between readability, accessibility and discoverability leaves us with the blues. Blue is the most typical and traditional color for links (Van Schaik and Ling), and users have grown to learn and trust that blue text is clickable.
I personally want uncluttered content, and in my mind lines belong only where I put them. So, my preference is for color-only-links. No underline. But our preferences are not ever the issue. What works is the issue. And links need to work for everybody.
Color alone vs. color + underlines
While underlined links are more accessible, the underlines clutter and make reading harder—particularly when there are many clickable items—as with lists, menus, tables of values.
- It is now trendy to leave out the underline and rely on color only. In fact, a university student recently wrote to tell us that no underlines was “modern”, and underlined links was “so old fashioned”.
- Popular social media sites don´t use underlines. Take a minute to recall how many links there are on a typical Facebook page, and imagine them all with underlines. (see image right)
The trendiness of sticking with color-only-links doesn´t change the fact that colorblind readers, older readers, and low-vision users may not see links if you leave out the underline. Clearly, hyperlinks should easy to see, and using color alone to indicate a link makes the links existence contestable for some readers.
Stats on color deficiency (iamal.com)
An important reminder to put this question in context:
- 1 in 12 people have some sort of color deficiency:
- 8% of men in the US are color deficient
- 0.4% of women in the US are color deficient and 95% of these are deuteranomalous
Below: the hex values for the blue links of well known sites including Google, Amazon, Wikipedia, Microsoft, Apple and Facebook. I made it to illustrate which color only links were easiest to see when using color-only link definitions. For the compelling opposing argument simuliate color blindness with any color you want.