What happened with Frostmourne?

Hi, i just come back from a few months break, i was playing on frostmourne when it was released, now i logged in, dalaran is quite empty, global / world chat is dead, and 0 pug raids in alliance side. What happened to the server? Ppl burnt out in ulduar?

Maybe people are working. Maybe they applied an update people didn't like and everyone returned to icecrown. Maybe there's really no rational answer to give here. Who knows?