Leading article: Twitter and the power of shared experience

The evolution of Twitter continues so rapidly and across such a wide front that assessments of its impact have constantly to be revised. But the extent to which it operates as a forum for shared experience and consciousness-raising has been brought home in the past few days by two remarkable streams of activity.

In the first, the novelist Linda Grant, responding to International Women's Day, instigated a series of tweets in which women recounted jaw-dropping tales of sexist treatment they had experienced. There was also, it has to be said, a funny side to these tweets, which was certainly not the case with the second stream. This one came in response to a Mumsnet rape awareness campaign – and what the tweets revealed was truly shocking. Self-selecting though such groups of tweeters may be, the value of their testimony cannot be denied. It amounts to instant and compelling social history that galvanises even as it informs.