Sir Alex Ferguson has announced his retirement from his role as manager of Premier League champions Manchester United and it has whipped Twitter into a frenzy.

In the first hour since he publicly revealed his intentions, there were 1.4 million mentions of the story on the social network. And the original announcement tweet by Manchester United's own account had been retweeted and/or been marked as a favourite more than 18,000 times.

The club posted the simple message "Sir Alex Ferguson retires" at 9.17am (8 May) and included the hashtag #ThankYouSirAlex. In the hour following, that had been used more than 100,000 times.

Even David Cameron, the Prime Minister, wrote a message on the site, although he couldn't help adding a comment about the team he supports, Aston Villa. "Sir Alex Ferguson’s achievement at #MUFC has been exceptional. Hopefully his retirement will make life a little easier for my team #AVFC," he posted.

The way the news spread is further proof that Twitter has become a valuable source for distributing information quickly. Among the millions of tweets about breakfast habits and postings of location-based information of interest to one person and one person alone, you can now get up-to-the-minute news without having to watch a finely coiffured TV host deliver it to you with bizarre inflections on words in weird places.

It's just ironic that many heard the news of the retirement of a man who made history on a service so geared for the future.