This is by far my favorite site, I visited every day since register, I will miss a lot. :(
Curse is sold to Twitch. Major issues with merging the twitch login. Curse focuses more on other things (cobalt and whatnot). Hearthpwn does not get the support for development it might have deserved. Traffic peaked during Un'Goro. Hearthstone netdecking site competition intensifies and the playerbase is shrinking some. Curse is sold to fandom, which has directly competing sites, like the hearthstone wiki. Major issues with transfering accounts because of data protection is again causing frustration among users. Curse is closing community sites but heartpwn still has a healthy amount of traffic.
Even without knowing the full story and the motivations for everybody involved, it is not to hard to see a pattern and a few causes leading to this tragic day.
Props to Fluxflashor for making the most out of a very tough situation!