Social media has become a massive indicator of real world engagement and sales, so much so that nearly every major company runs exclusive social media advertising campaigns. I believe Facebooks biggest revenue source is companies using it as an advertising platform.
Youtube stream with largest concurrent viewers:
When I watched I saw 2M on the ENG stream watching live on youtube. Correct me if I am wrong but I've never seen such numbers on youtube streams. 4.5M concurrent across all streams.
Twitch event with largest concurrent viewers:
Largest single stream concurrent viewership on Twitch was previously held by League of Legends tournament with 1.09M. When I checked mid stream, PS channel on Twitch had 1M.
Again from the image above, 2.7M concurrent across all streams.
Most liked announcement tweet in gaming:
Most liked gaming post instagram:
Hardware reveal youtube views:
SW: 43 million
PS4: 38 million
PS5: 24 million
XSX: 12 million
XB1: 7.5 million