All further knowledge related to some knowledge should be directly accessible!

Could you imagine the Internet without hyperlinks? Undoubtedly, hyperlinks are one of the key reasons for the success of Internet. It is so easy to click on an object and get additional information. Unfortunately, a lot of applications don't provide hyperlinks and are therefore much less user-friendly. This should be kept in mind when designing the user interface.

Here are some examples:

• Displaying a customer in an accounting application shows the total amount of unpaid invoices. Clicking on this amount shows the list of unpaid invoices. Clicking on one invoice of this list shows the invoice. Clicking on one line item of the invoice shows the product's data. Et cetera, et cetera
  
  
• An error displayed by a compiler should enable the programmer to have immediate access to any related information in the technical documentation, as well as to jump immediately into the source code containing the error.
  
  
• Whenever appropriate, context sensitive help should be available in a consistent, easy-to-use way.
  
  
• A good example of extensive use of hyperlinks can be found at www.amazon.com, one of the most popular and successful online shops. But be careful when visiting the site: you risk buying more than you intended ;-).

Although hyperlinks are widely used on Internet, they suffer from two inconveniences:

• Hyperlinks are not always visible in an unambiguous way. Blue, underlined text is not necessarily a hyperlink, and a hyperlink is not always blue, underlined text. Moreover, there is no standard for distinguishing hyperlinked images from images without hyperlinks. When the user wonders if a hyperlink is available, he has to move the mouse over the image. A better way could be to display a standard little button, e.g. a question mark, close to the hyperlinked object.
  
  
• Occasionally, more than one hyperlink exists for one object on screen. But in HTML there is no direct support for multiple hyperlinks. The click of an object's hyperlink could display a list of all available links in a standardized way.