The usefulness of the how-to videos on YouTube varies depending on the subject. There are many useful videos for simple things such as recipes or replacing batteries. However, more in-depth tutorials for things like computer programming are often lacking.
YouTube is a streaming video site with millions of videos related to nearly every subject imaginable. Its how-to section is extensive, but quite often, it's difficult to weed through all the less useful videos to find ones that are pertinent to the desired subject. There are, however, a great number of YouTube channels dedicated to nothing but how-to videos that can be great resources on a large number of topics.