Lucy Kellaway, the caustic and sharp-eyed business columnist at the Financial Times, picked up a complaint that Starbucks outlets in the UK have a vaguely lavatory smell and watched the company response. Of course, it helped that the Tweet came from the political satirist Armando Iannucci, who has 80,000 followers.

Her report:  Within minutes, Darcy Willson-Rymer, the UK head of Starbucks, had replied: "Thanks for your feedback. Which store did you visit?"

When Twitter first launched a few years ago, not many users knew what to do with it. It seems there were many tweets of the "Just ate lunch, about to sip my coffee" variety. People who got Twitter and had the time to devote to the microblogging service quickly started building followers, retweeting, and making the most of it. Everyone else was left tweeting about what they might have for dinner.

No more.