The inability to use a computer–for communication or commerce, or even for personal enjoyment–can severely limit one’s ability to function in today’s world. In short, being illiterate has to do with lacking communication skills, and those skills are no longer limited to reading and writing.
In Stuart A. Selber’s “Re-imagining the Functional Side of Computer Literacy”, Selber defines computer literacy as an aspect of “functional literacy.” Functional literacy is the ability to function according to the requirements of particular situational environments. An Amish person might be functionally literate if they can read, write, and raise a barn (A terribly stereo-typical generalization, but they aren’t reading this, so…). Whereas, to be functional in a University setting one may need fundamental know-how in a variety of digital media and applications (power-point, anyone?), as well as with the particular rhetoric of their chosen discipline. In short, literacy is both functional, and critical, and even environment specific.