Ferguson may be one of the old school but his retirement announcement was very much a 21st century event.
Manchester United broke the news on Twitter, and even their official announcement had the strapline #thankyousiralex at the top.
The club also arranged for fans to be able to write their own eulogies to Ferguson via that other social media giant Facebook, and the best of the messages will be put into a special book for the retiring manager.
Within an hour of the news breaking, there had been 1.4 million mentions of it on Twitter - by comparison it took four hours for the death of former Prime Minister Baroness Thatcher to top one million.
Within eight minutes of the announcement, it was the number one global trend on Twitter, with 140,000 uses of the #thankyousiralex hashtag inside of three hours.
Lewis Wiltshire, head of sport at Twitter UK, said clubs are increasingly looking to social media to make announcements.
He said: "Throughout the Premier League one of the developments we have seen is clubs breaking news on Twitter - QPR's sacking of Mark Hughes and hiring of Harry Redknapp were both announced on Twitter, as was Chelsea's hiring of Rafa Benitez.
"Clubs across the board are realising it is the best way to reach all of their fans at the same time, democratising the media so that their fans in Indonesia are getting the news at the same time as those in England."
The social media impact of Ferguson's retirement announcement fell short of Barack Obama's tweet after he was re-elected president of the USA, which has since been retweeted 850,000 times. The tweet United sent out on Wednesday morning received more than 30,000 retweets.