As far as Wikipedia goes I do allow my students to use it as a source. I ask them to trey and validate all the information they find by using multiple sources for the information that they include into their projects. I think allowing kids to use all types of sources and then try and validate that information with other sources gives them a realistic idea of how to find credible information. In my opinion Wikipedia may not be the best source for information but it often one of the first places that people can get information from. This is something that people tend to look for when accessing information. People want the quick easy answer, therefore, I think it’s a good idea to teach students how to get quick correct information.
At my school YouTube is blocked on all student accounts. Teacher do have access to the videos placed on YouTube. I don’t allow students to use youtube videos in their projects but I do use some videos for class. I show the students the Tony Gwynn OTL video from ESPN in my health class. https://www.youtube.com/watch?v=7pEAjphgW7s