Sources and references are clearly marked and a bibliography is often provided. Sites should be revised and kept current. Dates should be clearly marked. Links should be current. Changes to Web Sites Web pages can be changed or altered by the author at any time.
Pages can also move or completely disappear.
Information can go out of date. Web pages can be anonymously sabotaged or deliberately changed. It is a good idea to check the date of the last revision so that you know you are looking at the most recent site. The Internet is in many ways like a town from the old west. It has no sheriff and strangers are always coming into town looking for trouble.