"Make sure to give your video a provocative thumbnail. For example, this video (which got over 13 million views) used a thumbnail that was not really even related to the video itself."
It is crazy they openly encourage the community to do the same. It is the same as posting a provocative HN title unrelated to the post, creativity should be encouraged but not to the detriment of the community.
"Maybe you don’t need to be this extreme, but your thumbnail should be interesting..."
I do agree with about everything else in the article, it is just the reinforcement of behavior that is a personal pet peeve of mine got a knee jerk reaction. I think "thumbnail fixing" is the 3rd largest problem on Video Sharing websites behind Youtube's comment threads (#2, I had to squeeze that pet peeve in).
Now, when it comes to a provocative thumbnail that is relevant to the video...great advice.
Edit: By "I agree" I mean I feel comfortable taking your advice. Good read.