In fact, perhaps the most important reason to link to outside texts is to show that, perhaps unlike my friend, you are willing to acknowledge that you are taking part in a greater discussion. The more connection you can show between your ideas and outside texts, the more credence readers give your thoughts. To that end, links also serve as an immediate citation for the outside sources you bring to your work, sort of a documentation shortcut (although it is important not to rely on links alone when it comes to citing sources for hypertext essays). Connecting to other texts also gives readers the chance to continue their edification with additional resources, especially if the additional resources are more substantial in scope and research than the original. And sometimes links offer a deeper “showing” of a concept by connecting to a page with more detail or a visual or aural representation of that concept.
Linking is wonderful, but there are some caveats. First, linking doesn’t absolve us from quoting outside sources completely. We still should be prepared to offer short or even block quotes of important passages in the articles we refer to in our texts. We also need to remember not to go link-crazy. In “Link Theory: Keep it Simple, Pick Meaningful Words,” Steven Johnson quotes New York Times web site design director, Khoi Vinh, about a strong rule of the linking thumb:
"The important thing is to hyperlink meaningful text," says Vinh. "You're contributing to the overall semantic nature of the Web by linking meaningful text."
This rule—that is to say, the act of creating hyperlinks itself—requires that we writers be prepared to recognize what is “meaningful text” in what we compose. Welcome to the lifelong struggle. I mean, really, isn’t determining what is “meaningful text” what the practice of composition is all about?