Even more money could be made from actually playing video games, as opposed to just making them, now that Amazon is buying Twitch Interactive, Inc., the company behind Twitch, one of the most-visited websites on the Internet.

Amazon announced the $970 million acquisition Monday to a lot of surprise, as many people thought Google was interested in buying Twitch for $1 billion. It’s no surprise someone would try to pick up Twitch — the live video streaming service that features many people playing video games. It became the fourth-largest source of Internet traffic in the U.S. earlier this year. According to Amazon’s press release, more than 55 million unique visitors viewed more than 15 billion minutes of video from more than 1 million accounts in July alone.

That’s a huge amount of traffic, and a huge opportunity to monetize a growing audience interested in watching video games.

Strange as it sounds, sometimes it’s pretty fun to watch someone else play games. It’s like an extension of when you used to go over to your buddy’s house and watch them play a game. You watch as someone — more often than not a stranger — plays through a JRPG or a platformer or a shooter and feel what they feel as they interact with the game. There’s an entire genre of gaming videos called Lets Play, where people can watch a gamer do commentary or make jokes while playing through a game.

There are, of course, people who have monetized their Twitch accounts. Professional and so-called celebrity gamers make money off of the ads shown during their Twitch streams. People have even struck advertising deals with smaller game market sites through the amount of traffic they generate on their Twitch accounts. It’s an incredible feat, considering the main concept is just people watching people play video games.

But it’s a growing market, one that Amazon and other tech giants clearly saw as a huge gain. Amazon has the opportunity to put a link on a “Call of Duty” stream to the Amazon store, where viewers can pick up that same “Call of Duty” title. They have the opportunity to market even more eSports events and potentially tie Amazon advertising to larger video game event live streams like the Electronic Entertainment Expo. There are many possibilities.

It makes sense, and it’s a clear money train with no signs of slowing down. Amazon is staking a claim on games and it will be interesting to watch how that claim develops over the next few years.