Being able to critically evaluate a web site and disaggregate fact from fiction is part of the research process. Check out the bogus and hoax sites and tools for critical evaluation to teach students' good searching and evaluation strategies.
Check out the Tech Boot Camp site to create Web Wse Thinking.
When students don't have a clear picture of search strategies or web evaluation, they often use Google or Wikipedia to locate information. This can be dangerous, as shown in this video on the different "hits" students can find when using various search sites. MEL, Google, Wikipedia and more!