• Provide a lot of links to other sites, to establish your own credibility, and usefulness. Example:

• Point to particular pages, deep within the other site, rather than dropping the user onto a home page.
• In describing the target page, identify the owner of the site, so users can gauge the author’s motivation and trustworthiness. For instance:

• Describe the content. If the target page takes a position, summarize that idea. Show me why I should go to this page. Example:

• Whenever you offer a link to the outside, offer a way for the user to report if the link is broken. Example:

• Do not change your own URLs. If you must, redirect people to the same page, or the best substitute.

Strike a balance between quantity of links and quality of links you create. The more links, the more maintenance. …

Do not change your own URLs too often. The more often you change your own URLs, the more often others will have to change their links. …The more dead-ends people experience, the fewer visitors you will have.
—NCSA (1996)

Exactly who the publisher of a particular site—and who the sources of information in the site are—may be unclear to users. Therefore, the sources’ motivations, qualifications, and trustworthiness are unclear. All of this causes users to wonder about the credibility of websites.
…
Users rely on hypertext links to help assess the credibility of the information contained in websites. .. "Links are good information. They help you judge whether what the author is saying is true," one said. While reading an essay, one person commented, "This site is very believable. The author presents several points of view, and he has links for each point of view."
—Nielsen & Morkes (1997)

Communicate trustworthiness. … Connected to the rest of the Web with links in and out. Not being afraid to link to other sites is a sign of confidence, and third-party sites are much more credible than anything you can say yourself. Isolated sites feel like they have something to hide.—Nielsen(1999a)

Most Web sites project an unbearable lightness—just so much confetti unlinked to consequence of substance.—Lynch (2000)

Hyperlinks subvert hierarchy. —Levine et al (1999)

A few hyperlinks to other sites with supporting information increase the credibility of your pages. If at all possible, link quotes from magazine reviews and other articles to the source. —Sun(2000)

Unnecessary links to outside sites may confuse or annoy readers, slow them down, and damage credibility. But when links to outside sites are carefully chosen, and when they are current and functional, they can further a site’s credibility. —Spyridakis (2000)

Make your links as direct as possible. If you can point to a specific area on a Web site that contains the information you are referring to, do so. We want readers to be able to access that information and not have to click through several intermediary screens.—America Online (2001)

See: America Online (2001), Berners-Lee (1995), Levine et al (1999), Lynch (2000), NCSA (1996), Nielsen (1999a), Nielsen & Morkes (1997), Spyridakis (2000), Sun (2000)