In the preceding two articles, I’ve reviewed some issues of reliability and legal liability for external links. In this final article I discuss policies about external links from corporate Web sites.

Last year, Apple agreed to make a small change to its rules for so-called “reader” apps (those that provide digital magazines, newspapers, books, audio, music, or video as their primary function).

Apple has changed its App Store rules in the U.S. to let apps link users to their own websites so they can buy subscriptions or other digital goods. This change comes after a U.S. court ruled in favor ...