One of the most popular channels on YouTube is aimed toward people who play video games. It's got tons of content — thousands of game reviews, how-to videos of people gaming away enthusiastically, even little homemade movies that people have made using video-game software.
That last format is a user-generated phenomenon called machinima — "little m" machinima. "Big M" Machinima is a company, and it wants to be a new media empire.