The original dates and dates of revisions are not always included. Many Web sites are trying to promote a product or service . The distinction between facts and advertising is not always clear. One Web page often links you to different Web sites . You'll need to evaluate these separately.
Web sites come and go.
They may be here one day and not the next. Retrieval of all information on a Web site may require additional software . If you do not have the software, you could miss crucial information needed for evaluation. Search engines may put you into only one page of a Web site. Put the page in context by going to the site's home page.