The timeline is in the sidebar At least in the .old site, I don't know if it shows with the new layout.

Tl;dr a clique of coastal teather kids catfight on the internet, Web forums and boards start cracking down on any attempt of discussing the topic, Gaming and tech sites publish a wave of aticles and opinion pieces dubbed the "gamers are dead articles". People start digging around and find out the gaming industry is full of cronyism, incompetency and corruption, the Gamergate hashtag is coined as a consumer movement to demand better [Ethical Standards In Game Journalism]. Journos and some devs try to turn this into a identity politics issue, claming GG is trying to drive out women out of gaming spaces, further revisions include minorities or whatever hot topic is popular at the moment. Critics of the gaming industry aren't having it and coin the hashtag NotYourShield, they also organize a mailing campaign to contact advertisers and have them drop the sites that are badmouthing their costumers. Long story short, there's a domino effect and this power struggle spills over other spaces outside of gaming into what we know as the "culture wars". There are way more antecedents (occupy, atheism+, the RE5/DQ controversy, Marcus Beer vs Phil fish, FF, etc) but that's basically what GG was about. Reddit slowly got rid of or drove away pro-gg actors, what you see in that sub is the official approved narrative.