I believe in traditional literacy. I believe that to be literate one must be able to read and write. I do not believe that there is a different type of literacy required for reading an internet article rather than reading a novel. I do not deny that interfaces affect the text and reader. Interfaces require different amounts of attention and skills of the reader, and interfaces often present differing levels of reliability.
When I say that literacy is the ability to read and write, I am aware that a large group of people with varying amounts of education and intelligence are included. But, that is what literacy is, our most basic organized communicative skill.
I believe that interfaces do not have to complicate this simple definition. Navigating different interfaces does not require different literacies; it merely requires different skill sets. Using a table of contents in a textbook and navigating the web are separate skill sets, not separate literacies.
How interfaces affect the text and the reader is important. Does a book or the internet require more attention from the reader? From which interface does the reader retain the most information? I believe that these are matters of preference and circumstances. Some find working with a pen and paper time consuming, and they find room for a bookshelf a luxury. Others think that computer screens are too difficult to focus on and that the bright light hurts their eyes. People just prefer one method to the other for different reasons.
I remember when my grandfather first started using e-mail. He is a smart man, but my mom had to explain to him how to use it, and it still took him the better part of an evening to set up his account. Six or seven years later, he still has the same dial up connection and e-mail address. I am not sure if he even uses it that frequently; he prefers to write. I have changed internet connections and providers several times in that period of time, but I am no more literate than my grandfather. Sometimes older generations never fully receive a new interface and they fail to learn its required skills, but they still have old interfaces and they remain literate and fully capable.
I also believe that certain interfaces are more reliable than others. Books undergo extensive screening through publishers, so they are extremely reliable. Whereas Internet articles sometimes go straight to the web and are less reliable. I have been in classes where teachers specifically point out web sites they will not count as a source because they are deemed unreliable. However, I have never had a teacher discredit an entire book. Both have their appeal, reliability as opposed to speed. Again the decision between the interfaces is a matter of preference.
I believe there is something good to be said of every interface and that each will continue to find its place in the literate world of the future.