You can find an example on the HD Live website (an annual web design event hosted in lovely Hull):

The HD Live website navigation menu. It used to consist solely of icons.
I guess this is an improvement on the previous Mystery Meat Navigation effort. But I’m left thinking: why not just use text? Icons are a bad idea because:
- unless the icon’s meaning is clear, visitors have to guess at its meaning and then look to the text for confirmation. This creates cognitive dissonance.
- when icons are used in applications they have a single, clear purpose. They often represent simple actions that can be performed across different applications (cut, paste, open file, close file etc.), while the meaning of less common icons can be learnt as the application is used over time. The meaning of entries in a website navigation menu are often less clear: they may represent places as well as more complicated, abstracted actions (archive, find out about something, etc.), and visitors are not going to learn their meaning through repeated use.
It strikes me that website navigation menus should always be rendered as text. The only exceptions I can think of are when a link leads to a place with a clear, branded icon (such as a Twitter account). Even then, you’re relying on all your users knowing what the Twitter bird looks like.