picture - How one picture changed the nature of the debate about migrants in Europe.
On the 2nd of Sept, a picture showing a 3 year old Turkish boy dead on the beach first appeared on social media, where it became widely shared. Traditional media soon followed suit, and Aylan Kurdi's picture became the defining image of Europe's migrant crisis.
Credited with prompting a major shift in public opinion, it bolstered the #RefugeesWelcome movement, and sparked a response from Europe's leaders after months of shifting the blame. In Britain, within 3 days of the picture being posted, David Cameron announced that the country would welcome 20,000 more refugees by 2020.
But was it right to share the picture of a dead child in the first place?
#Black Lives Matter - Police killings of young black men in the US have not escalated in number - they've been alarmingly frequent for years. But this hashtag, started in 2014 but with tens of millions of uses this year, has galvanised a protest movement at a scale not seen since the 1960s. Why now?
#Distractingly sexy - Following comments made by the Nobel scientist Sir Tim Hunt, the hashtag #distractinglysexy started a worldwide debate on sexism in science with female scientists poking fun at the idea that they were a cause of distraction in the lab.
But the hashtag also led to a polarised debate about whether Sir Tim Hunt had been fairly treated amidst the Twitter storm his comments provoked.
A debate that still rages on, and that - some argue - is distracting from the original intention of the hashtag.
- How a fringe newspaper became a worldwide symbol for freedom of expression - and tested the limits of satire.
Ever since it was created in the 1960s, Charlie Hebdo has always prided itself on being "mean and nasty" and on holding nothing sacred. And yet, earlier this year after 10 of its staff were killed in a shooting, its name has inspired one of the world's most recognisable slogans "Je suis Charlie", a rallying cause for free speech, which spread around the world via social media and inspired many causes.
The recognition and support brought the paper wealth and an international audience, but also a level of scrutiny it had never experienced, with its past and current covers now being shared around the world, debated and often criticised as people argue over the limits of satire.
- How a dress from Birmingham became the year's biggest talking point as people debated which colour it was - dark blue and black or white and gold. For some, the debate suggested an existential crisis over the nature of sight and reality, which could go as far as harming interpersonal relationships. Others expressed their dismay at the triviality of the whole dispute. Was discussing the dress a huge waste of time, or did we learn something in the process?