Activision Blizzard Media claims the recent Major League Gaming Counter-Strike: Global Offensive Major Championship set some viewership records for an esports broadcast. Here's a bit along with the relevant footnotes:

Activision Blizzard Media Networks, a division of Activision Blizzard, Inc. (Nasdaq: ATVI), today announced that Major League Gaming's Counter-Strike: Global Offensive Major Championship (CS:GO Major) set new viewership records during its March 30 - April 3 broadcast from Columbus, Ohio. Audiences generated 71 million video views,(1) watched a record-breaking 45 million hours of live broadcast(2) and set a new record of 1.6 million concurrent viewers(3) across OTT, web, mobile and in-game streaming during this year's event.

This breaks the previously-reported CS:GO Major record of 34 million hours viewed and 1.3 million concurrent viewers set at the 2015 CS:GO Major in Cologne, Germany.(4)

(1) Data provided by MLG.tv, Twitch and GOTV
(2) Data provided by MLG.tv, Mars.tv, Twitch and GOTV
(3) Data provided by MLG.tv, Twitch and GOTV
(4)ESL Press Release