VIDEO: #MarriageEquality in Ireland was one of Twitters most talked about subjects in 2015

The hashtag #MarriageEquality, which dominated social media around Ireland’s historic vote to legalise gay marriage, marked one of the most talked of moments of the year on Twitter.

In its review of the year, the social media site revealed #JeSuisParis hashtag, along with #PrayForParis, used to show solidarity with the French capital in the wake of its second terrorist attack, were the most used on the micro-blogging site in 2015.

This was followed by the Black Lives Matter movement, which began in the US and has become a social campaign discussing police brutality against black citizens. The hashtag or phrase was used more than 9m times in 2015.

However, with same-sex marriage being legalised nationally in Ireland and the US this year, #Marriage-Equality was driven up to third on Twitter’s list of most popular posts.

#HomeToVote, used by Irish citizens who returned to Ireland to cast their ballots in the referendum, and #LoveWins which trended on June 26 when the US Supreme Court confirmed the legalisation, also dominated for spells.

There's a monstrous queue to get into Ireland this evening. Guess what they're all back for? #MarRef pic.twitter.com/IP811asPV1

— District (@districtireland) May 21, 2015

Lewis Wiltshire, Twitter’s director of media partnerships, said: “2015 has been another phenomenal year on Twitter. Across the world people have come together to celebrate, support one another, to show solidarity and of course to laugh.”

As refugees fleeing war in the Middle East flooded into Europe, debate raged on Twitter over how to deal with the situation, with #RefugeesWelcome dominating the site enough to reach fourth on the influence list for the year.

As always, football leads.#RefugeesWelcome pic.twitter.com/42eNWku9Uc

— Stan Collymore (@StanCollymore) September 2, 2015

This was followed by #IStandWithAhmed, a trend in support of Texas schoolboy Ahmed Mohammed, who was arrested when the home-made digital clock he had in his bag was mistaken for a bomb. Images of teenage school children in handcuffs went viral, and more than 370,000 tweets were sent — including one from US president Barack Obama.

Cool clock, Ahmed. Want to bring it to the White House? We should inspire more kids like you to like science. It's what makes America great.

— President Obama (@POTUS44) September 16, 2015

National elections in Britain, Canada, and India combined to be sixth on the list, while the top 10 was completed by the women’s football World Cup, Nasa’s Pluto flyby in July, #TheDress which divided the world over whether it was blue and black or white and gold, and Caitlyn Jenner joining the site following her gender transition.

Ms Jenner gained 1m followers in just over four hours, earning her a Guinness World Record.

Another Jenner world record, and at 65? Who'da thought! Humbled & honored to have reached 1M followers in 4 hrs. Thank you for your support.

— Caitlyn Jenner (@Caitlyn_Jenner) June 1, 2015

The number of Twitter users grew to 320m globally this year.