In the science of Human Information Behavior, Carol Kuhlthau identified this information literacy issue and the process of becoming literate in finding information as the Information Search Process (ISP). The first step in information literacy as identified by Kuhlthau is teaching the user to identify the question they are trying to answer. The librarian's job is to help the user define the question and then assisting the patron in locating and evaluating that information. After evaluating the information, the 21st century librarian should also be a resource in teaching the patron how to use that information.
The reason why librarians must teach information literacy is essentially "teaching a man to fish." There is no argument that librarians must be masters of information literacy, but by teaching similar skills to users, the library patrons become effective searchers and gain a better understanding of how to navigate the increasing amount of information that is being published. The fact that so much information is being digitized is not an argument to get rid of physical libraries, but an argument to keep libraries around so that everyone can find information that is both authoritative and useful.