Software from Sentius Corporation, Palo Alto, CA (www.sentius.com) that embeds annotations within a document so that readers can obtain further clarification of a word or phrase that is unfamiliar to them. When reading the document, clicking an annotated word pops up a menu with links to definitions, images or other Web sites. RichLink software for Windows and Mac is used to embed documents with proprietary material or with entries from RichLink-formatted dictionaries and encyclopedias from third parties.

The RichLink software accepts text-based documents, Web pages and e-mail messages and outputs a proprietary format that can be viewed with a Web browser or Acrobat Reader plug-in. RichLink authoring and viewer plug-ins are available on the Sentius Web site.