In the YouTube community there's a bit of a kerfuffle over the fact that Nintendo has been doing two things. First, they've been taking down Let's Play videos because of copy right infringement. The second is they've been putting ads on those videos they aren't taking down. I don't believe that either of these should be allowed. As always, I'm not a lawyer - keep that in mind.
Let's Play videos are essentially play through of a particular game. Nintendo is claiming that they own the copyright to video because they created the content that is in the game, including the text, music, artwork, and characters. This is of course completely true. However, they don't own everything in the video. The person doing the let's play makes choices so, while the overall story arc is in fact the same, the manner in which the game is completed is unique and can happen in very different order. Which means if Nintendo owns the copyright of the way you play it, then it owns every possible way the game could ever be played. I could see that there's some logic to that argument, however, it's impossible to predict how the game will play out any given time and it also means that Nintendo also owns every time the player fails to beat the game and gives up.
If this was the only thing in the video, I'd say Nintendo has a decent argument, but even then it's something of a remix, because things are being changed, events happen randomly that aren't under Nintendo's control, they set the parameters for something to happen, but they couldn't predict a priori when something was going to happen or what items would be dropped at any given time - which makes the game different each time.
Furthermore, many of these videos have voice overs by the players. In many cases the players are talking about things completely unrelated to the actual game which Nintendo cannot claim as their own copyright. In many cases it is actually the YouTuber that is driving viewership to the video and not the game alone. Of course if you don't like Pokemon you're not going to sit and watch a 45 minute play through of Pokemon even if you find the person hilarious (or you might). It's the personalities that make these videos valuable as much as the Nintendo game material.
I also think that Nintendo needs to put this in perspective of other mediums that people do a similar type activity. Think of someone analyzing a film, a book, or TV Show - in all of these cases there are direct quotes, clips of the video or whatever with pausing and zooming and highlighting and whatever. In addition there is custom material that the specific critic ads to the video which makes it something new. This constitutes Fair Use. These reviews make the film more valuable because it draws viewers to the movie, the is the same for video games.
Nintendo doesn't understand this and it's likely to be contested, eventually Nintendo will lose this and will have lost a lot of good will from the gaming community. This will end poorly for Nintendo.