I recently visited the Bauhaus University in Weimar, Germany and recorded a podcast with professor Christoph Engemann.
Christoph asked me to select a text that I felt was canonical for digital studies. While several candidates came to mind -- from Donna Haraway, to Claude Shannon, all the way back to Euclid's Elements -- I decided to nominate the short text "Postscript on Control Societies" by Gilles Deleuze. We spoke for about a half hour on the text and how it relates to digital theory more generally.
If you are interested in more, I gave a longer lecture on Deleuze's "Control Society" essay in 2011 at UMass, Amherst. And this material formed the basis of chapter five on computers in my last book.