The pope does it. Obama does it. So last week I finally decided to open a personal Twitter account to “join the conversation,” as friends had urged. I signed up to follow some of them, and others in the foreign-policy community¸ and then waited for something to happen.

It soon did. It was a tweet on Friday that first alerted the world to the killings in Norway. It did not take long before thousands of #Norway and #Oslo tweets were voicing their thoughts and spreading the views of the experts from the mainstream media and the blogs across the twittersphere. From the Washington Post and New York Times to the BBC, the working theory was that there was a link to the Muslim extremists of al Qaeda. I retweeted to my 17 followers a piece by Max Fisher from The Atlantic on “Al Qaeda’s problem with Norway,” despite my better judgment and the caution of the local police, who would later announce that the suspect was a Norwegian.

On Twitter, on Friday, there was a lemming-like rush over the cliff. The prevailing view was the echo chamber of the experts. Their certainty, before the suspect had even been captured, troubled me. On Saturday, after The Sun in Britain had published its front page, trumpeting: “Al Qaeda massacre, Norway’s 9/11,” the tweeting lemmings had done a U-turn and were heading en masse for another cliff. By then we knew that the person who had bombed the government quarter and then massacred Norwegians at an island youth camp was a right-wing extremist. Twitterers were listing the roll call of shame and demanding apologies from the media whose experts had gotten it so completely wrong. Again, in the herd mentality, there were no dissenting voices. They were in a place of exclamation marks, not question marks.

What did all this tweeting achieve? Precisely nothing. It did not add to the sum of knowledge. In the absence of hard facts it filled the vacuum with rumor and false information. If this was a conversation, it was not one that I wanted to join. By the time I switched off my computer at lunchtime on Saturday, the lemmings were off again. #AmyWinehouse was leading the Twitter trending and #Norway was nowhere to be seen.