It is the symbol that has helped propel political movements, promote social media influencers and streamline online communication — and today the humble hashtag turned 10.
On this day a decade ago, the social hashtag was born when Twitter user Chris Messina proposed utilising it to bring a group together.
The global trend kicked off from there, spilling over into other forums like Facebook and Instagram, and even into spoken conversation.
Ten years later, the symbol is used for far more than creating groups — the hashtag is now shared about 125 million times every day on Twitter alone.
Hashtags have become a force for political movements and a means of showing support during times of tragedy or triumph.
Following the Sydney siege, #illridewithyou sprung up in support of Muslim Australians, a movement that was later echoed as #illwalkwithyou in the US.
#BlackLivesMatter has made the leap from hashtag to mass movement in the US, in protest of police violence against unarmed African Americans.
And hashtags have also been used to highlight and tackle sexism, from the #IAmMyOwnGuardian campaign in Saudi Arabia to the #CoverTheAthlete campaign that took off during the 2016 Rio Olympics.
#5SOS and #auspol among Australia's top hashtags
But they have not always been used for serious reasons.
Hashtags have been used by bloggers and so-called social media "influencers" to cultivate massive number of followers.
They also allow widespread groups to join discussions in pop culture spheres — the most tweeted television show is #TheWalkingDead — or to group or provide context to a social media post.
After all, where would we be without #ThrowbackThursday as an excuse to post an old holiday photo?
"The hashtag changed everything — over the past ten years, it has become one of the most widely recognised and used symbols in the world," Twitter Australia managing director Suzy Nicoletti said.
"It created new ways to communicate, to share, and to build communities."
She said Australia's top hashtags included social movements like #illridewithyou and #ChangeTheDate in support of moving Australia Day from January 26, #5SOS — used by passionate fans of band 5 Seconds of Summer — and sporting events like the #MelbourneCup.
The ever-trending #auspol is also among the most popular hashtags in the country, having been used more than 3.5 million times.
"It's a mix that speaks to our unique culture, sense of identity and sense of humour," Ms Nicoletti said.
