Hypertext information links are typically contained in documents accessible by networks. Data is gathered regarding the results of attempted access to documents identified by these links. The link's viability is calculated based on the number of successful attempts resulting in successful access in order to provide a measure of link viability. The display of the document is altered based on the measure of link viability. An average of link viability for all links on the document, and on the site, is used to calculate document viability and site viability which can be used to rate the document and site, respectively. These viability measures are displayed along with the corresponding link, document, and site. Display of results retrieved by conventional search engines may be sorted based on link, document or site viability, and displayed accordingly. Links contained in bookmark lists are also measured for viability to cull out bookmarks with low link viability to, or low document viability of, the bookmarked document. Viability calculations may be made by a user computer device, an Internet Service Provider, a third party service, and/or a server on which a document resides.