When people access online information using assistive technology, they have the ability to view a list of all the links available in a document or webpage. Using descriptive links is important for these users so that they don't end up with a list of links all called "Click Here". In other words, the text of the link should make sense out of context. Here are some compliant and non-compliant examples of descriptive links.
The following image demonstrates what a links list looks like when the links are non-compliant. Notice that this list would be basically useless on its own.
This image shows a links list that utilizes descriptive links. Notice that each link has at least a basic indication of where it will lead.