n. The ability to read and write using multiple media, including traditional print media, electronic devices, and online tools.
Other Forms
Academics at De Montfort University are researching the nature and impact of a new kind of literacy: the sharp end of modern communication known as "transliteracy". The term describes the ability to read, write and interact on a range of platforms. Think of the media's teenage stereotype, a young girl watching Hollyoaks on television while simultaneously discussing its plotlines on the social networking site Facebook, listening to music on MySpace and texting her friend to discuss home study….

At De Montfort, Sue Thomas, a professor of new media, is more interested in the impact that transliteracy is having on higher education and pedagogy. In these terms, many academics are in essence illiterate, says Thomas. Most would admit it, even taking a certain pride in their part- removal from the world of e-communication. This matters if they find their teaching relationship with hyper-transliterate students breaking down because of an inability to communicate fully with one another.
—Hannah Fearn, “Grappling with the digital divide,” The Times Higher Education Supplement, August 14, 2008
According to Penley, we need to see video images and text messages as an evolution rather than a devolution of literacy.

Penley's colleague Alan Liu, an English professor, agreed: "Our kids are reading and writing like crazy," he said.

In 2005, Liu launched a UC-wide project, Transliteracies project, which has scholars studying the evolving definition of literacy in the digital age.

Among the things that make online reading unusual is that it adds a social dimension to literacy, Liu said. "We're researching what reading and writing is becoming if you redefine it to include this whole, thick social zone."

"We need to learn from them (teens)," Penley said. "Transliteracy is not starting from, 'It's bad,'but, 'What is reading in the digital era?'"
—Kim Lamb Gregory, “Pages turn to the next chapter of youth literacy,” Ventura County Star, August 19, 2007
2005 (earliest)
The Transliteracies 2005 conference (Conversation Roundtables on Online Reading) assembles a distinguished group of theorists and practitioners from the humanities, arts, social sciences, computer science, and industry to talk about the fate of reading in the "new media" age. The conference initiates the Transliteracies research initiative.
This term is a modern update on the older sense of transliteracy that referred to using or being fluent in all aspects of print media. An even older sense (mid 19th century) is the verb transliterate, which refers to substituting the letters of one language with the letters of another that have the same or a similar sound. (For example, replacing an accented e in, say, a French word, with a regular e for use in an English text.)

Wikipedia claims that transliteracy comes from this older verb, but that's obviously wrong. (What!? Wikipedia wrong!? Say it ain't so!?) Transliteracy combines literacy with the prefix trans- , which means "across; through", so a transliterate person is one who is literate across multiple media.