Fair use does not require a license, that's why it's fair use. Period. If a gaming video is considered fair use is different on a video per video basis and some developers might actively try to shut you down more than others. But you CAN make money off video game footage. If you don't want to take my word for it, just go look at the hundreds of channels actively monetizing CoD footage and making quite a few bucks off of it.
As for networks having licenses; the chances they have a license for every single video game every made is virtualy impossible. They may have agreements with major publishers but in the end you hardly ever need it. Hell I mailed EA once to ask for permission and they simply told me that they are fine with monetizing footage of ALL their games. Company policy, so I was told. EA is THE biggest player in the industry, which makes it abundantly clear how useless those licenses are.
Additionally, fair use in this case is often heavily in favor of YouTubers. The footage is unique and altered since every single recording is by definition different and everyone plays in a different way. Footage is often educational or for review purposes and teaches the viewer something about the game (how to play it or if it's good or bad). The footage NEVER takes away from the copyright holder's income because viewers can not play the game and the person playing has already paid for his/her copy. In fact in almost all cases the footage is considered free advertising and thus a positive influence on the copyright holder. And in some instances it can even be argued that while the game is property of a developer, the footage of said game is made and owned by the person who filmed it. And lastly there is no true breach of copyright because nothing is being copied. We are not taking the games and selling them for profit. We are merely showing off the game someone else has made to an audience.
Because of all those things it would not only be very risky to bring such a case to court, it would also be insanely stupid. YouTubers essentially make free advertisement for the games in question. A game developer would have to be very stupid to try and take that down. At the very most they might claim the video and put their own ads on them, but the chances of getting a copyright claim because of them are slim to none.
This thread is very old (from 2013), and the original posters may no longer be active on these forums. Therefore, I am locking this thread to prevent confusion. Feel free to start an updated discussion on this topic. A lot has changed regarding YouTube's Monetization Policies, and I recommend double-checking the latest agreements with game developers and YouTube monetization before posting videos. ^_^