We analysed data for the websites of the BBC, the Guardian, the Daily Mail, the Times, the Telegraph, the Express, the Independent, the Sun, the Mirror, ITV News and Channel 4 News, counting the number of times a story's URL was mentioned on Twitter.
Half of the top ten are picture or video stories and, compared to previous years, the most tweeted story in 2013 is almost four times higher than that of 2011 and nearly 40 per cent higher than that of 2012.
Top 10 Twitter stories of 2013
1. BBC: Gay marriage: Supreme Court justices criticise Doma
Total: 319,047 tweets
2. BBC: Reeva Steenkamp's brother: 'We want to remember her goodness' (video)
3. BBC: Brazil nightclub fire kills 'at least 230' (video)
4. BBC: N Korea 'combat posture to hit US'
5. MailOnline: Britain braced for a white Easter: Blizzards and icy blasts all week... then get ready for a heatwave next month! (picture story)
6. BBC: Take a tour of The Shard's viewing platform (video)
7. BBC: HMV music and film chain to appoint administator
8. The Guardian: Falkland Islands: respect overwhelming 'yes' vote, Cameron tells Argentina
9. MailOnline: Mind you don't trip! Paris Hilton steps out in an overly-long strapless playsuit for a day in Beverly Hills with boyfriend River (picture story)
10. The Telegraph: Cheltenham Festival 2013: Bobs Worth wins as Nicky Henderson claims Gold Cup with jockey Barry Geraghty