Providing links that allow the user to skip directly to content, bypassing the navigation, enhances the accessibility of your web site. This is recommended for blind or visually impaired users, people who use screen readers, and also for text-browsers, mobile phones and PDAs (Personal Digital Assistants).
These links are common on most US, UK, Irish, and other government websites, as well as many universities and private organizations.
From the accessibility and usability point of view, it is recommended that you make such links visible. Why?
In his article titled "Providing Skip Links", Frank Gayne of frontend.com explains:
"Skip links would be useful for people who cannot easily use a mouse. Many of these people depend on tabbing in order to make progress through an interface and might appreciate a skip links feature to lighten the amount of work they have to do. If there is no visible focus to let these people know they have hit a link, then this useful feature is lost to them."
How can you build such links? Immediately after the logo of your web site, insert the skip link: "Skip to main content". Does the link have to go after the logo? Many web sites have the "Skip to main content" links before the logo of the page, but a logo is the precursor of a web page. It lets the user know what website he/she is on.
For example, if a Screen Reader user clicks an internal link on your page, your logo's alternate text attribute tells the user that he/she has not yet left your website. If the "Skip to main content" link is before this logo, then the user does not know immediately which website he/she is on.
In many occasions, web site developers or their clients do not wish to have the "Skip to main content" link visible, with the excuse that it does not fit in their design. In this case they might use a technique wrapping the accessibility text or links in an HTML div setting it to display: none or visibility: hidden.
The problem with this technique is that it does not always work as expected. Some screen readers do not speak material that is marked display: none or visibility hidden, and others depend on how the style is specified. To solve this problem, you could make them invisible with the technique of using transparent graphics.