#BringBackOurGirls

In April 2014, heavily armed Boko Haram terrorists stormed a school in northern Nigeria and kidnapped more than 270 girls. Although some 50 girls were able to escape, the remaining ones were reportedly married off to the militants for somewhere around $12 each (nine euros). Some are believed to have been forced to carry out suicide attacks in Nigeria.

Within a week of the abductions a social media campaign under the motto "Bring back our girls" was launched. Its goal was to raise awareness and pressure Nigeria and other governments, to intervene.

The hashtag #BringBackOurGirls went viral over the course of several weeks:

It saw a number of prominent backers like Michelle Obama and Malala Yousafzai, who survived an attack by the Pakistani Taliban, which was aimed at silencing her for promoting girls' education. While the campaign has managed to keep itself afloat throughout the year, both Nigerian and international forces have failed to find the girls. More women and children have been abducted since.

#BlackLivesMatter, #ICantBreathe, #CrimingWhileWhite, #Ferguson

#ICantBreathe, #CrimingWhileWhite and #BlackLivesMatter were the main hashtags used on Twitter to protest police violence towards black people. They were a reaction to the death of the teenager Michael Brown in Ferguson and Eric Garner in New York. Both were unarmed.

Demonstrations took place in several cities across the United States. They gained an immense following after US courts decided not to indict the white police officers involved in the shooting of Brown and the fatal headlock of Garner. Continued reports of similar incidents and the retaliatory attacks on police officers have kept the discussion alive.

#MyDressMyChoice, #BeenRapedNeverReported

Sexual harassment, cat-calling and abuse were topics that saw regular debates on Twitter and Facebook. The #MyDressMyChoice campaign began in November 2014, after a woman was brutally assaulted outside a Nairobi bus stop for wearing a miniskirt. The attackers accused the victim of tempting them because she was wearing 'indecent' clothing. The incident was captured on a video that was published on YouTube and caused an uproar in Kenya where protesters took to the streets in support of her.

A month earlier, #BeenRapedNeverReported took off as rape survivors shared their experinces online. The trend was started by Antonia Zerbisias, a writer for The Toronto Star. Zerbisias shared her own experience in support of Canadian actress Lucy DeCoutere, who had accused a former CBC radio host of assault. Other users were quick to join and share their own experiences.

The Ice Bucket challenge

The Ice Bucket Challenge started in July 2014 and went viral when celebrities got involved. The goal was to raise awareness and much needed funds for research into amyotrophic lateral sclerosis (ALS). Physicist Stephen Hawking, probably the most famous ALS patient, sits in a wheelchair and communicates through a voice computer controlled by his eyes. ALS destroys nerve cells, leading to muscle paralysis. To draw attention to this, CEOs, pop stars, actors and footballers tipped buckets of water over their heads and the videos generated millions of clicks - and millions of dollars. Estimates suggest that 150,000 people worldwide suffer from ALS.

#OccupyCentral: The Hong Kong 'Umbrella Revolution'

Thousands of Hong Kong students took to the streets as they protested against the China's plans to regulate the selection of Hong Kong's chief executive, starting 2017. Despite being part of China, Hong Kong citizens were in the pas able to elect their own leader, but this year, people felt that their freedom was being compromised.

Hashtags such as #OccupyCentral, #HK, #OccupyHK and #UmbrellaRevolution were used massively by protestors.Although the media attention has faded, protests are still taking place and police arrested dozens of people in the last week of the year. Earlier in December, police cleared protest sites, while the demonstrators vowed to return - and they did.

#AyotzinapaSomosTodos, #yamecanse, #43

In early October authorities in Mexico uncovered a mass grave in the southern state of Guerrero. The burial pits were located near a town where 43 students disappeared after Iguala police shot at buses that the students had seized to return to their teacher training college.

Thousands of protesters took to the streets to commemorate the disappearance of the students. Among the most viral hashtags used for tweeting about the events were #43, #YaMeCanse (I'm tired or I have had enough) and #AyotzinapaSomosTodos (We are all Ayotzinapa).

#NotInMyName

Young people in Britain turned to social media to fight propaganda by Islamic extremists. The 'Not in My Name' campaign took off as young British Muslims appeared in videos to send out the message that the radical Islamist group IS does not represent them or their values.

The videos gained wide support. US President Barack Obama even praised the campaigner for their courage. Other Muslim groups have however criticized the campaign, saying that Muslims are not responsible for the actions of extremists and shouldn't have to publicly apologize for them.

The hashtag was later used by other campaigns, including Israeli citizens who objected to Israel's military operations in Gaza and Americans who showed their disgust at torture methods used by the CIA in its hunt for terrorists worldwide.

#PEGIDA, #HoGeSa, #NoPegida, #Schneegida

Autumn 2014 saw the inception of the anti-Islamization group "Pegida" - a public campaign that mobilized thousands of people in Dresden. Pegida supporters see the group as a justified criticism of how Germany deals with immigration issues. Similar demonstrations took place in several cities around Germany and a football hooligan protest in Cologne turned markedly violent.

But Pegida also sparked resistance movement, accompanied by the hashtag #NoPegida (and its spoof version #Schneegida). It was used by Germans who wish to see a more diversified Germany and who were shocked by the new upsurge in right-wing ideology. Germany's Chancellor Angela Merkel used her new year's speech to criticize the group.