Wikipedia has been known to be a good foundation or go to for information. It does show up first in all searches for information. I'll admit I do like Wikipedia because it seems to have just the facts, rather than opinions and lists several categories and "further reading". Having said that, I have been told during my entire undergrad that, "sure, use it as a frame of reference but double check the facts and don't take it as 100% factual." In other words, take a look, but double check the sources.
When thinking about it though, I imagine it would be difficult to post to Wikipedia without subconsciously having some sort of bias. I also remember reading an article about one author/poster who spends a lot of time filtering through Wikipedia. His issue is a certain phrase. I can't remember specifically what the phrasing was, but I recall it was grammatically correct. He just has an issue with it, so he spends all his free time searching all the Wikipedia pages seeking out this phrase and editing it to reflect basically the same meaning, but a difference in choice of wording.
I have myself followed the same guidelines when guiding my students in research, don't take it as the holy grail, but is is a resource of some value. Check the sources, seek out other well known reputable sources and cross reference. I myself use Wikipedia frequently as well as the links posted in the reference section.
Both articles posted on CNET claim that Wikipedia is a valid source (although with a 1/3 more errors than Britannica), as much as the Encyclopedia Britannica, although it's pointed out that Britannica is not infallible either. The author also points out both sources have mistakes or misinformation in a study. With the push in the academic and business world, there is always the push for collaboration and Wikipedia does use collaboration in a very broad way including users and experts in all fields and industries.
In terms of YouTube, school tube, and teacher tube, I'll admit I use Youtube much more than the latter two. The reason for this is simply accessibility. The selection and variety on Youtube is much wider and many more choices than the other two. Admittedly, I have not tried school tube and teacher tube in some time. I will have to investigate to make a more informed decision. However, when I had tried it, I could not find videos that had exactly what I was looking for. Youtube has a much larger variety. I do need to watch my students closely because they do like to click suggested or popular videos when they think I am not watching, and some of the videos/ads are risky and inappropriate. But I have never not found what I was looking for on Youtube. I also like that I can subscribe to channels and they will be emailed to me when a new video is posted. The students easily recognize Youtube and it usually gets their full attention. I also like that teachers post tutorials and lessons that they have made and uploaded. You can find many grade level books being read by teachers as well, eliminating the need for me to purchase out of my own pocket. I also use Youtube for studying/relaxing music when students are doing independent and group work. If I forget, many of them ask me to turn on the "concentrating music". Learnzillion, which is a resource recommended by the common core website also has complete lessons with slides and tutorials specific to each standard. Since I have to find most of my own resources, this has been extremely invaluable. I have an app for the common core and they list recommended resources. Also, this app is much easier to read than the huge sections on the Common Core website (https://www.masteryconnect.com/teachers). They also have a resource pinner which allows access to resources and assessments other teachers have pinned.
Another added benefit of Youtube is accessibility. Many websites have a share link specifically for Youtube, making it simple to add a video to the classroom website or uploading a screencast. I;m not sure about the other two, but I also use the "embed" feature quite frequently. My philosophy on using technologies has been pretty consistent. I am looking for ease of use, user friendly for the grade level of my students, and availability of resources aligned to the common core.