Criado-Perez received a disturbing number of rape and death threats on the social media website this July after successfully campaigning to keep women's faces on banknotes in the United Kingdom. She reportedly received no support from Twitter when she attempted to draw attention to the abuse. British politician Stella Creasy received similar abuse when she allied herself with Criado-Perez, and in the following days, a number of unrelated female public figures received bomb threats via tweet.
When news of these scandals reached the public, over 125,000 people signed a petition demanding Twitter make changes in its policy to ensure that this kind of harassment does not go unchecked. Twitter responded Saturday with an update to the Twitter Rules that explicitly prohibit targeted abuse, as well as a promise to add a "Report Abuse" button in every tweet. This new feature has already debuted on Twitter's mobile website and the Twitter app on Apple devices, and will reach Android devices and Twitter.com itself sometime next month.
Local police are still investigating Criado-Perez's harassers. It is unclear to what extent their online actions will be punishable by UK law.
Meanwhile, Twitter's UK General Manager Tony Wang has taken to his personal account to do some damage control. He tweeted these apologies along with the announcement of Twitter's policy change: