While League of Legends creeps up on the National Hockey League in terms of numbers, MLG is quite happy to boast that its "[v]iewers consumed more than 54 million hours of MLG’s online video in 2013 vs. 14 million hours of video consumed by NCAA March Madness Live viewers."
As a whole, "MLG online video consumption was up 262% over 2012 and 1557% since 2010." The eSports leader is clearly barreling forward. It recently announced its own premium streaming platform, MLG.TV, meant to circumvent the likes of Twitch and UStream. I wonder how long until the PS4 and Xbox One get MLG.TV apps. I wonder how long before I won't instinctively type "MLB" first. Hopefully never.
One other fun tidbit of data: 90% of MLG.TV's audience is male. Maybe that accounts for all the growth.