Yes, I would advocate for multi-literacy. This could be represented by a primary and secondary skill set. For example, if someone consistently went online to learn new things and solve problems but was reading a great deal of text such a Wikipedia entries, then I would say that she was post-literate with a secondary focus on literate skills.
I just tracked down the definition of "media literacy" from the National Aaaociation for Media Literacy Education: "Media literacy is the ability to encode and decode the symbols transmitted via media and the ability to synthesize, analyze and produce mediated messages." This looks to be the closest that I have to a definition of post-literacy.