It is more than knowing how to use the computer. It is more than knowing how to send an email. It is more than using the cadre of Microsoft products. It is about rhetoric, audience, message, purpose. It is about design, using image and word, and minimizing possible misinterpretation. It is a science. It is an art.
To learn about digital rhetoric, read Aristotle , Socrates (my personal favorite), Foucault, and Paul Gilster .