The whole #GamerGate problem started with a lover's spat that quickly spiraled out of control. A woman named Zoe Quinn, a game developer who designed the game "Depression Quest," was given a scathing review by a jilted ex-boyfriend who had a popular blog.
The review was more of an open letter that attacked her character and accused her of sleeping with game review writers to boost good publicity for her games. There were also several screenshots of private conversations and personal details revealed about her life to the Internet that had nothing to do with her game or her professional life.
The one gaming reviewer in question had dated Quinn once but had never covered her game or wrote reviews about her company. He quoted her once in an unrelated article months before they dated and never wrote about her again.
The initial post was discovered by 4chan users, who are widely regarded as the most troublesome scum on the Internet, and they began attacking Quinn. Her accounts were hacked, and she began receiving death threats, rape threats, and threats against her family. Personal information was discovered and leaked online in an attack called "doxxing" and Quinn was ultimately driven offline and out of her home to an anonymous location for safety.
Perhaps the worst part about these attacks is not just that they happened, but that many people online accused Quinn of lying and making up the abuse to gain popularity and get donations for her (free) game. They also accused her of using her "womanly wiles" to sleep her way up the ladder in the gaming industry.
Quinn's opponents and attackers created the hashtag #GamerGate and tried to claim that the reason they were disparaging her was because it "an ethical debate about the relationship between gaming press and game developers."