The Marriage Equality referendum, Charlie Hebdo and "that" dress were among the topics that got Irish Twitter users talking in 2015.

The social network was the platform for some of the most hotly contested debates on the internet, as well as spreading some of the most heartwarming moments of the year.

Following 2014’s “year of the selfie”, 2015 was the turn of the emoji, with the face with tears of joy the most popular on Twitter. There were plenty of emojis being used in May when Ireland became the first country to legalise same sex marriage by popular vote.

More than 400,000 tweets using the MarRef hashtag were sent, as people took to the polls to cast their vote. In the list of top five hashtags for Ireland, MarRef, VoteYes and YesEquality took the top three spots.

A further 72,000 tweets were sent using the HomeToVote hashtag, when Irish citizens returned to use their vote in the referendum. Also on the top list of discussions was the ongoing campaign to repeal the Eighth Amendment of the Constitution, which came in at fourth position.

When it came to TV talk, #vinb was the most-used hashtag, with the Eurovision song contest at third and the Rose of Tralee in fifth place.

Irish Water and the right to water campaign were top of the political trends, with the Budget16 hashtag coming in at third place in the list of most-tweeted hashtags.

On a lighter note, Twitter was also a forum for one of the most hotly debated subjects of the year, when the discussion over whether a dress was black and blue or white and gold went viral.

More than 4.4 million tweets were sent on February 26th and 27th as people argued over the optical illusion and explained the science behind why the dress appeared to be different colours to different people.

Among general news trends, Greece, November’s Paris attacks and the Charlie Hebdo attack in January were the most- discussed hashtags on Twitter.