Usability is the ability of a person to use something. In regard to CAI provided on the Internet, this means the ability of users to learn what they want to know. The important aspects of web site usability include navigation, readability, comprehension, and speed of completion. Authorship means the Web sites should present the information about authors, such as the author's qualifications which are relevant to the content, contact information, and copyright. Furthermore, they should present sponsoring institutions.
Content validity means how reliable and free from error the information is.
There are many criteria to evaluate the content validity, including currency, coverage, linking, and freedom from bias. The first criterion is currency. Currency refers to the timeliness of information. Consumers should consider how often that Web site is updated. The next criterion is coverage.