Twitter Inc encountered a user revolt for the first time as a public company after it tweaked its "block" function on Thursday, prompting an outcry from those who said the new policy empowered perpetrators of online abuse.
Users could previously prevent their harrassers from following them or interacting with their tweets. Under the new rules, a blocked user can view or tweet at the person who blocked him or her, but that activity will be rendered invisible to the victim as if the offending account did not exist.
Twitter said Thursday that the change was meant to protect victims of harassment who wanted to filter out abusive messages but feared that the act of blocking a user would prompt retaliation.
Responding to a wave of criticism, Chief Executive Dick Costolo said on Twitter Thursday evening that the new features were widely requested by victims of abuse.
But many were not convinced. Within hours, the service was flooded with angry users, including many who did not understand the nuances of the new policy and hundreds had signed an online petition to reverse the change.
"New @twitter block policy is like a home security system that instead of keeping people out puts a blindfold on YOU when they come in," said user @edcasey.
"Just ignore them & they'll stop" is a dangerous thing to say to bullied kids & a dangerous thing to say to stalked/harassed Twitter users," wrote @red3blog, another user.
Keeping abuse in check is a sensitive issue for the company, which needs to keep hold of existing users and attract hundreds of millions of new ones to justify the stratospheric valuation that investors have placed on its stock.
Twitter shares have risen 35 percent to $55.33 the past two weeks on investor expectations that the company can sustain its growth for years and mature into an Internet powerhouse.
The changes were announced Thursday after the market close.
The controversy highlighted Twitter's growing dilemma over how it should police the freewheeling service or stamp out abuse.
Twitter, which once espoused a radically hands-off approach to moderating content, was pressed in August to strengthen its "report abuse" functions after two high-profile women in the United Kingdom, feminist and journalist Caroline Criado-Perez and Labour Party politician Stella Creasy, were subjected to a deluge of death and rape threats.
Twitter's top executive in the U.K. Tony Wang, and Del Harvey, the head of its trust and safety team, issued personal apologies to the women after revising Twitter's rules.
Executives rushed into a meeting Thursday night at Twitter's San Francisco offices to discuss the uproar, a rare event for a company that for the most part has historically been hailed for championing its users, who now number more than 250 million worldwide.
Although Twitter has made unpopular design tweaks, it has maintained a better policy record than social media rival Facebook Inc (FB.O), which has repeatedly upset users over the past decade with abrupt changes to its privacy policies.