My initial thoughts were that such density in Ironforge is not much compared to Vanilla or TBC high pop realms(1) from back in the day(2), and that latency is painful to watch. Then he went outside and that explained the latency and also represented probably the largest crowd I've seen in one place. I hope Morhaime and some of the other guys at Blizzard see this video.

(1)By calling it a realm instead of a server I suppose I out myself as a former WoW GM.

(2) Fairly typical player density early in Vanilla (in an atypical and hillarious situation): https://www.youtube.com/watch?v=CZ_WdYvwrDA

The server had 5x the population of a reatil Vanilla realm. Those were capped at 2,500 but Nostalrius regularly peaked near 13,000 concurrent players.

Their second server was also reaching ~5,000 players at the time they were shut down.

I was a raid leader/main tank for the guild who got the first ever Nefarian kill. We announced on forums that he dropped a head quest similar to Onyxia that turns in at Stormwind and people started flooding our server with new humans, thousands of them. It was insanity. To no one's surprise turning in the quest crashed the server...

It was honestly better in every single way than any vanilla WoW server ever was. Average online at any given time was >10,000 people.

When Nostralius surpassed blizzard in active players, they had to step in ;)