Here's a good example of how it can really work well: PronunciationBook. The series could not be simpler. It demonstrates the pronunciation of common words, names and brands. It's nothing fancy (and commenters, of course, often beg to differ) but that's why it works, particularly if you're watching it in the Cosmic Panda interface, which makes watching a series seamless and easy.
YouTube's Cosmic Panda Beautifies Viewing Experience
YouTube's new interface makes simple PronunciationBook series shine