Twitter product manager Aliza Rosen in a post on the company’s blog:
We want every person around the world to easily express themselves on Twitter, so we’re doing something new: we’re going to try out a longer limit, 280 characters, in languages impacted by cramming (which is all except Japanese, Chinese, and Korean).
It was really only a matter of time. I always appreciated Twitter’s forcing of brevity—there were definitely times I didn’t tweet something because it didn’t fit into 140 characters and you know what? The world didn’t end. It probably makes sense for them to update for the times, now that we’re not all using SMS to submit our tweets (as was the source of the original character limit), but it is going to mean losing some of the charm of what made Twitter what it was.