How hashtags evolved in the aftermath of the Christchurch earthquake: 

I returned to the Twitterstream which had now exploded with tweets mentioning “new zealand”, “earthquake” and “christchurch”. And pretty soon the first hashtags started forming: #earthquake, #quakenz, #nzquake, #nz, #christchurch and combinations of these. And of course there was the inevitable question after Indonesia, would there be a #tsunami? By around 5am one hashtag began emerging: #eqnz.