4.2. Distinguish links from the surrounding text
When links are included in content, they must be distinguished from the text surrounding them, not solely using colour. For example, the links could be underlined.

Note
This rule does not apply to links included in link groups (menu items, for example), because their function is obvious.
Warning
You are strongly advised not to apply underlining to other elements than links.
Tip
In addition to this recommendation it is also a good idea to provide the mouse-over appearance of links in the mock-ups.
The change of appearance when mousing over the links must not be limited to a change of color (other possible additions : removed underlining, bold characters or an added icon, etc.).