I am involved in the business of advertising and marketing; yet, I have not noticed what you have alluded to even though I try to be aware of such things, since it's a way of soliciting new business. However, what I have noticed is the power of YouTube provocateurs to make or break a product. What is so discouraging about it all is some of these highly influential product reviewers do not have the credentials to profess on their topic; yet, non-critical thinkers still seem to take the bad advice. An example: In the arena of Marksmanship Training, I watched about a dozen YouTube videos about how to sight-in a rifle the other day. None of these videos mentioned how to apply sight adjustment from linier bullet displacement at target to minute of angle correction on the rifle, which is essential to the process. This revealed these purveyors of knowledge did not have enough knowledge of the subject to be teaching the concept. At any rate, seems to me, marketers today need to be cognizant of YouTube, or no matter the marketing strategy, their product may be rejected by the market.