There’s nothing that signals widespread cultural impact of something than when major advertisers and brands start taking notice — and spending money. That’s where eSports is now, rising from an obscure sliver of the gaming market to a commanding presence that’s on every major publisher’s radar. Several recent studies have provided significant data to illustrate just how important a force eSports have become in the game industry and beyond. The fact is that eSports are not just something that game marketers should be aware of – eSports are something that every marketer should be aware of and taking into account when planning marketing campaigns.

The latest figures on eSports from research firm SuperData show that viewership of eSports has grown from 72 million in 2013 to 101 million in 2014, with 134 million viewers predicted for 2015. The growing popularity of eSports is illustrated clearly by Amazon’s purchase of Twitch for $970 million earlier this year, with Twitch boasting of more than 55 million monthly viewers.

Market research and consulting firm Newzoo has been compiling information on eSports from 25 individual countries, and a recent Newzoo report looked at the growth and popularity of eSports as a global phenomenon. The company estimates that eSports Enthusiasts, which it defines as “frequent viewers and active participants, will reach 145 million by 2017. That’s not even counting the very large group of consumers that watch occasionally (once a month or less), which Newzoo feels illustrates “the immediate potential for explosive growth.” Newzoo estimates the current global eSports audience at 205 million, counting both the 88 million enthusiasts and the 117 million casual eSports fans.

Newzoo sees a compound annual growth rate of more than 20 percent between 2014 and 2017 for eSports enthusiasts globally. “Following the recent boom of eSports in the West, North America is amongst the fastest growing regions with 14 million Enthusiasts and another 18 million Occasional Viewers this year,” said Newzoo’s report. Newzoo also looked at a measure that’s extremely important to marketers: Awareness. “Global awareness of eSports will grow by a CAGR of +21.6 percent over the next three years, resulting in 1.2 billion people that are aware of eSports by 2017,” said the report.

The stage is clearly set for major brands and advertisers to take advantage of this large and rapidly growing market. That’s what a New York-based agency, Sparks & Honey, concluded in a recently released report on eSports. The company’s research found about 300 million epsorts fans in 152 countries “who watch games such as League of Legends, Dota 2, Call of Duty and StarCraft 2 online through streaming platforms like Twitch.tv and MLG.tv.,” reported Forbes. “An average viewing session lasts 2.2 hours with more than 2.4 billion hours watched in 2013.”

This massive, dedicated audience has already captured attention from major players interested in this young, highly engaged demographic. Some major brands are sponsoring events and players, including Coca-Cola, Intel, Red Bull, American Express and Nissan. “They’re starting to pay attention and the great thing about it is it’s not just one game. An advertiser can get involved with just one game like Intel has with StarCraft 2 or try a variety of games,” said Imari Oliver, Sparks & Honey’s director of creative strategy.

As an example, the recent Intel Extreme Masters tournament in San Jose, California welcomed over 6,000 people on Saturday and 6,500 on Sunday to watch top League of Legends and StarCraft II players compete at the SAP Center, where the San Jose Sharks play. The event marked the ESL’s (eSports League) biggest eSports event ever held in the US. “The event can only be labeled as historic,” said Michal Blicharz, Director Pro Gaming at ESL. “We had never done anything like it in the U.S. — in terms of magnitude, number of fans or streaming results on Twitch. It’s a stepping stone towards doing even more impressive things.”

When eSports events are gathering purses as high as $11 million for DotA 2‘s The International, or an audience of 27 million viewers like the League of Legends World Championships in October, it’s clear that eSports is on a par with many longtime sports like pro golf or hockey. When you have brands like Coca-Cola and American Express spending serious money to support eSports, that’s a signal to marketers that this segment of gaming has arrived as a force to be reckoned with.

Game publishers are certainly taking note of this as well, as every major publisher is re-examining its game portfolio to see what might have strong eSports potential. It’s pretty clear that Microsoft’s game design for Halo 5 (due out in 2015) is heavily slanted towards making the game a compelling eSport. This is only fitting, as the original Halo was one of the major drivers behind the creation of eSports. Along the multiple versions of Halo since then, though, the game lost its ability to provide a balanced arena for competitive play, and fell out of eSports competitions just as eSports were beginning to be significant. Now Microsoft hopes to reclaim a spot at the eSports table, seeing that grabbing the attention of over 100 million eSports fans would be a useful way to generate more sales of the Xbox One console.

The rise of eSports isn’t just restricted to consoles and PCs, though that’s where almost all the action is now. Mobile game developers are trying to grab a share of that market, as the recent release of Vainglory for iPads and iPhones shows — and the game has been featured in Apple’s iPhone ads, giving it a strong boost. It seems inevitable that Vainglory or some other mobile game will eventually become an eSport capable of drawing millions of fans to watch competitors battle for millions of dollars.

Meanwhile, savvy marketers should be thinking of ways to utilize this eSports phenomenon to their advantage, through sponsorships, partnerships, promotions, endorsements, or advertising. That competition is already under way, and the marketers who win at eSports stand to reap millions.