According to The eSports Observer, which has been tracking livestream data on Twitch, the Riot Games MOBA has racked up nearly 100 million more hours of watched gameplay compared to the same period in 2018.
Fortnite saw a roughly 12% decrease in viewership over the past year, though the game still compiled an impressive 465 million hours of watched gameplay, firmly establishing itself in second place.
The data from 2019 also shows the astonishing increase in the popularity of Grand Theft Auto V likely spurred almost entirely by its roleplaying community. Rockstar's game was at the fringes of the top 10 most popular games during the same period in 2018, only to rise to the third most popular game on Twitch so far this year, and the fourth most popular section overall, behind the "Just Chatting" section.
"Just Chatting", which was classified as "IRL" in 2018, also increased steadily, pointing to the popularity of content not directly related to video games on Twitch. Talk shows and podcast make up the majority of "Just Chatting" streams along with an array of daily life broadcasts such as trips to the gym, cooking or traveling.
PlayerUnknown's Battleground fell out of the top 10 most-popular games completely this year after hosting a respectable 232 million hours of content in 2018. Filling the void appears to be Apex Legends, the battleground game released in February, over a month after the data collection period began.
Both Overwatch and Counterstrike: Global Offensive, games with heavily-backed eSports scenes, saw slight declines in viewership numbers. Hearthstone's popularity also fell, while World of Warcraft more than doubled the amount of viewed hours in the period. In May, Blizzard released a closed Beta for many popular Twitch streamers to play its anticipated WoW Classic relaunch, which will go live in August.
Overall, the data shows how quickly games rise and fall in popularity on Twitch, though a handful of long-standing titans like League of Legends and Dota 2 continue to hold impressive viewership numbers. If any game not currently in the top 10 is likely break in during the second half of 2019, it may be another Riot Games title. Teamfight Tactics (which unlike Dota 2's AutoChess is classified separately from its "parent" game League of Legends) has been a mainstay in the top five game categories since its release last month.