Evaluation of Authority and Credibility in New Media - How are you going about this?

I'm working on an issue of Knowledge Quest and, at the same time, a presentation for Charlotte AASL called Who Knows What and How Do We Know It?

"Information evaluation is the single most important concept that we are responsible for teaching. Yet once our mini-lessons are done, the online tutorials completed and the research essays submitted, our students abandon our pathfinders and checklists in the dizzying stew of click-and-go wikified information where anyone can claim expertise. We'll analyze trust, expertise and authority in the real and online world and examine a framework for developing shrewd and skeptical learners."
(see here for others)

I've got a great conceptual piece about how we should be doing this but now I'm looking for short examples of practices. How are you asking students to evaluate new media - I thought responses would be of general interest to everyone...