#HometoVote, which dominated social media around Ireland’s referendum to legalize gay marriage in May, was one of the most influential global hashtags on Twitter in 2015.

The legalization of same-sex marriage in Ireland and in the United States this year caused Twitter to light up on both sides of the Atlantic. In Ireland #HomeToVote was used by Irish citizens who returned to the Republic to cast their ballots in their hundreds while in the US #LoveWins trended on June 26 when the US Supreme Court confirmed the legalization.

From all of those hashtags dubbed the “biggest impact” by Twitter what’s refreshing and somehow reassuring is that they are supportive and positive message of support or solidarity. Something that is often lacking in social media and online chatter.

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.”

Just after the marriage referendum on May 22 Twitter’s HQ, in San Francisco, acknowledged Ireland’s winning hashtag by posting it on their wall of fame. Within 24 hours the hashtag had been tweeted 27,000 times.

According to Twitter these were “the moments that had the biggest impact across the world”:

- #PrayForParis and #JeSuisCharlie – in support of the people of Paris surround two devastating Islamic terrorist attacks on Paris in 2015.

- #BlackLivesMatter – a hashtag which represented a social movement. This was tweeted nine million times this year surrounding deaths and violence in Ferguson, Charleston and Baltimore in the US.

- #HomeToVote and #LoveWins - in support of and celebration of marriage equality. Twitter reports that “HomeToVote hashtag became hugely popular when Irish citizen expats shared their experience returning home to vote in the gay marriage referendum on May 21.”

- #RefugeesWelcome – in support of people from the Middle East and Africa seeking refuge in Europe.

- #IStandWithAhmed – in support of a 14-year-old schoolboy, Ahmed Mohammed, who was detained and handcuffed at his Texas school for bringing in his homemade digital clock. They believed the high school freshman was in possession of a bomb. This hashtage was tweeted 370,000 times.

- The “national elections in Argentina, Canada, Singapore, India, and the UK dominated the civic conversation.”

- #FIFAWWC – FIFA Women’s World Cup in Canada this summer sparked a global conversation online.

- #PlutoFlyby – as Nasa’s New Horizons spacecraft, which launched in 2006, came within 7,750 miles of Pluto’s surface and took photos of the planet. Their photos generated over one million tweets.

- The famous Top Shop dress – was it #BlueandBlack or #WhiteandGold. Who knows but what Twitter can tell us is that it sparked 4.4 million tweets.

- As for the person who made an impact Twitter lists Caitlyn Jenner who generated over one million followers having introduced herself to the world. She managed to break the record of @POTUS, the President of the United States.

#HometoVote top influence on Twitter for 2015: Thousands of people celebrate the Yes Result in the Marriage Equality Referendum in Dublin Castle.RollingNews