Why this? Gaming is a passion shared by millions of people. It's a sport, hobby, pastime, and even an escape for some. Gaming is one of the most popular activities ever! Billions of dollars every year are put into creating, developing, and purchasing games. People play games casually or competitively. When playing competitively you can either range from the level of a stick to a legend, anyone that is a legend is usually professional. These professionals usually participate in tournaments. During the tournament members of the community come together to watch the epic showdown between the best players in the world. A few notable tournaments for games would be WCS Global Playoffs and Finals (StarCraft), World Championship (League of Legends), and World Electronic Sports Games (CS:GO and Dota). The winning team of the tournament always wins a large prize pool. This is why most people try to become professional, so they can earn a living off doing something they enjoy. The few games listed here are only scratching the surface of games that are played competitive and have large professional communities.
Stated in the last paragraph the way most people get noticed in a game community is from streaming and YouTube videos. These people also always stand out in the community because leaderboards. Everyone always starts out as a confused, helpless player. However through countless hours of playing and mastering your skills you become better. Usually games have an in game ranking system. Once you're good enough you will achieve the highest rank. By then you know you are ready to go pro. That's when someone would start making YouTube videos or streaming themselves play. With this recognition joining a competitive team would be the fastest way of getting into tournaments. That's when money starts coming in.
The current most paid professional gamers come from the game Dota 2. For the past three years the biggest tournament held for the game has been the number one on the charts for highest prize pool[1]. Just last year (2016) the Dota 2 tournament prize pool was over twenty million dollars. The crazy thing is that there a multiple tournaments held every year but many, many more games.
One of the most disregarded things about being a professional gamer is how much effort goes into achieving this rank. The best players for gamer usually have been playing since the game was released and haven't given up or people that joined the community and pushed really hard and always gave their best effort. People that just join the community stand no chance against these guys. In now way is this job or career not fit for the rewards.
Some more of the interesting facts about gaming in general is that most players are indeed male[2]. I think this should come to no surprise. Something to note about competitive professionals that there aren't any or very few in the communities that were talked about. Lastly, the most common age of the gaming community is 18-35[3].