When US Representative Gabrielle Giffords was shot in Tucson on 8 January 2011, several reputable news organisations, Reuters, NPR and the BBC among them, wrongly reported on Twitter that she had died. The episode revived a familiar argument about how fast false information travels on the network.

The post’s position was that the accuracy problem in breaking news was not new; newsroom editors had faced the same pressures in the late 1990s and early 2000s, before Twitter existed. What had changed was pace. Dan Gillmor had argued for a “slow news” approach, taking a deep breath and digging deeper as a normal part of media use, but the post judged it unlikely that the rapid-fire cycle would slow down.

Two forces were identified. The first was immediacy: information moved in near real time. The second was distribution: a message grew exponentially as people along the network rebroadcast it to friends, colleagues and acquaintances.

The more interesting point was where the checking had moved. Journalism had always been a messy process, but it used to happen behind closed doors, as reporters and editors weighed conflicting reports and decided what to publish. On Twitter that process was taking place in public: information was published, disseminated, checked, confirmed or denied in the open, in a collaboration between professionals and the public. The traditional sequence of filter, then publish was being inverted into publish, then filter, with verification carried out in view of everyone.