Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A typed link in a hypertext system is a link to another document or part of a document that includes information about the character of the link. For example, rather than merely pointing to the existence of a document, a link might also specify that the document supports the conclusion of the article pointing to it, that it contradicts the article pointing to it, that it is an older version of the document, that it serves to define the word next to the link, that it is an index to other documents of the same type, or some other relationship. This allows a user to take actions such as searching only certain types of links or displaying them differently. It may also allow browsing software to do things like pre-fetching documents it expects the user to browse.