Well, I'm not really for skipping learning about WWII, but learning how to use Wikipedia and how to blog sound like excellent things to teach kids. Should we really teach kids that knowledge comes from a single authoritarian figure like a teacher, or should we tell them that they need to investigate numerous versions of the view of history?
Two words come to mind: citation needed. It's interesting to note that the foundation of open, aggregated knowledge-building relies a relative handful of trusted sources which are closely and jealously maintained by trusted authorities. That is, topic experts which have an understanding of not only the basic facts, but the contours, concepts, and unique questions that arise in a given subject.
A student doesn't know what they don't know. A teacher is not simply a dispenser of knowledge, but ideally, is a guide, helping a student to understand those contours, concepts, and unique questions, along with the basic facts (allowing that student to form their own opinions and interpretations).
Without the guidance of a good teacher, a student may absorb information uncritically and in a fragmentary fashion, creating an incomplete and erroneous understanding of the subject. So, the role of a teacher is dynamic and relational. Moreover, there are unspoken aspects of knowledge that are difficult to transmit through the written word.
Now, of course, there are plenty of people who are self-taught, but even the best autodidacts rely upon sources written by experts to attain their knowledge, as well as learning from others. That mixture of the hierarchical and egalitarian, the open and the authoritative, is an essential balance, each maintaining the integrity of the other.