On the 23rd of August, 2007, Chris Messina, a former Google designer suggested that Twitter adopt the hashtag or “pound” symbol, as some called it at the time, as way to bring groups on the internet together.
Ten years on, with an average of 125 million hashtags shared every day on Twitter, it's hard to imagine the internet ever existed without it.
Hashtags are proving a powerful way for social and political movements to start conversations.
One of the most defining examples of this is #BlackLivesMatter campaign, which began as a hashtag to draw attention police-related violence in the United States.
It's also used in the online sphere of sports, politics, pop-culture, entertainment and satire.
To celebrate its birthday, here are some of the most memorable #hastags movements in Australia, and around the world.
In Australia
One of the biggest movements to start on Australian Twitter is #putoutyourbatsout, where cricket and non-cricket fans alike shared pictures of bats on their doorsteps to honour the death of Phillip Hughes.
Related reading
Put out your bats trend honours Hughes
Sydney dad Paul Taylor tweeted a picture of a cricket bat near his front door with the hashtag #putyourbatsout.
The hashtag soon gained momentum with cricket fans and friends from London to Chicago posting their personal tributes to Phillip Hughes.
#illridewithyou is another example, when Aussies banded together to say no to racially motivated violence after the Sydney Siege.
While #Changethedate, a hashtag calling for the date of Australia Day to change, has grown exponentially in the last few years.
Since it was first used in 2014, it's grown by more than 5,000 per cent.
Australians have Tweeted almost half a billion times with hashtags supporting homegrown boy band '5 Seconds of Summer,' while political junkies have used the #Auspol hashtag 3.5 million times.
Suzy Nicoletti, Managing Director of Twitter Australia says Australia's top Twitter hashtags reflect our interest in a broad range of topics.
"You’ve got everything from social movements like #illridewithyou, to passionate fans of #5SOS, iconic sporting events like the #MelbourneCup and the ever-trending #auspol," she said.
"It’s a mix that speaks to our unique culture, sense of identity and sense of humour. It’s #whatshappening.”
Around the world
- The most Tweeted about movie hashtag of all time is #StarWars
- The most Tweeted television show hashtag of all time is #TheWalkingDead
- The most Tweeted gaming hashtag of all time is トレクル (TreCru/Treasure Cruise) with over 269 million uses of the hashtag
- The most Tweeted global sporting event hashtag is the #Euro2016
- The most Tweeted team hashtag is #MUFC.
