Hashtag

The # symbol itself has ancient roots. It traces back to the Latin abbreviation *lb* for *libra pondo* ("pound in weight"), which scribes wrote with a horizontal line across to indicate abbreviation. Over centuries of hasty handwriting, that ligature morphed into the # we know today6. The symbol appeared on typewriter keyboards in the 1870s and was added to Bell Labs' touch-tone telephone keypad in 19685.

The practice of using # to organize online discussions started on IRC (Internet Relay Chat) networks around 1988, where chat rooms were prefixed with the symbol followed by a topic name3. But IRC hashtags were limited to people actually in the room.

Chris Messina, a Google user experience designer who earned his communication design degree from Carnegie Mellon in 20037, brought the concept to Twitter. On August 23, 2007, he tweeted: "how do you feel about using # (pound) for groups. As in #barcamp [msg]?"1. Two days later, he published a detailed blog post titled "Groups for Twitter; or A Proposal for Twitter Tag Channels," arguing that the # convention could let Twitter users follow topic-based conversations without needing to follow each other directly8. He cited the March 2007 South by Southwest Interactive conference as an example of where hashtags would have been useful.

On August 28, 2007, web anthropologist Stowe Boyd responded with a blog post where he coined the actual term "hash tag" to describe the concept4. Messina pitched the idea formally to Twitter co-founders Biz Stone and Ev Williams, but they reportedly told him hashtags were "for nerds" and would never catch on5.

Hashtags fundamentally changed how information spreads online. They gave ordinary users the power to create and join conversations at scale, without needing permission from any platform or gatekeeper.

In marketing, brands built entire campaigns around hashtags. Calvin Klein's #MyCalvins encouraged users to post photos in their underwear. Red Bull's #PutACanOnIt promoted creative photos with their product. Expedia's #ThrowMeBack campaign offered travel vouchers for nostalgic posts5. But brand hashtag campaigns also backfired spectacularly at times, as companies discovered they couldn't control how the public would use an open tag.

In politics and social justice, hashtags became organizational tools for real movements. The Arab Spring protests, Occupy Wall Street, Black Lives Matter, and Me Too all used hashtags as rallying points that could spread faster than any traditional organizing method5.

Messina, the inventor, never attempted to patent the concept. "They were born of the internet, and owned by no one," he said3. He continued working in tech and is recognized by Carnegie Mellon University as a notable alumnus7.

Twitter finally built official support for hashtags on July 2, 2009, hyperlinking all hashtagged words in tweets to search results3. This was nearly two years after Messina's original proposal, but it changed everything. In 2010, Twitter introduced "Trending Topics" on its homepage, displaying the most popular hashtags in real-time. The company started selling sponsored trending topics to brands like Disney, Coca-Cola, and Hyatt for a reported $100,000-$120,000 per day18. During the 2010 World Cup, Twitter deployed "hashflags" that replaced three-letter country code hashtags with national flags3.

The 2009-2010 Iranian election protests marked a turning point for hashtags as tools of political activism. Twitter users employed both English and Persian-language hashtags to coordinate and share information during the events3. This set the template for a decade of hashtag activism that would follow.

Other platforms took notice. YouTube began supporting hashtags, and real-time search services like Google Real-Time Search incorporated them3. Instagram, which launched in 2010, made hashtags central to content discovery. Posts with at least one Instagram hashtag averaged 12.6% more engagement than those without18. Facebook added hashtag support on June 12, 2013, though its implementation was limited by privacy settings. Users could only see public posts and content shared by friends, unlike Twitter's fully open search model19. LinkedIn, Tumblr, and Pinterest followed with their own implementations.

Hashtags also found powerful applications in social justice. The #BlackLivesMatter hashtag, started by activists Alicia Garza, Patrisse Khan-Cullors, and Opal Tometi in 2013 following the acquittal of George Zimmerman, gained massive mainstream attention after George Floyd's death in 20205. The #MeToo movement, originally started by Tarana Burke in 2006, went viral as a hashtag in 2017 after revelations about Harvey Weinstein5. Other notable hashtag campaigns include #JeSuisCharlie, the 2014 #IceBucketChallenge, and #BringBackOurGirls.

Beyond activism, communities worldwide used hashtags to challenge dominant media narratives. During Kenya's 2013 elections, Kenyans on Twitter created #TweetLikeAForeignJournalist to mock sensationalized international coverage, with tweets like "BREAKING: Masked men with sticks spotted fighting violently at a Fencing club"20. Similar campaigns like #UgandaIsNotSpain (after Spain's PM made a dismissive comparison) and #Ottawapiskat (turning Canadian government criticism language back on Ottawa) showed how hashtags gave historically underrepresented communities a way to reach global audiences through humor20.

On January 4, 2013, the American Dialect Society voted "hashtag" as the 2012 Word of the Year, beating out "YOLO," "fiscal cliff," and "marriage equality" in a vote by more than 250 linguists, lexicographers, and historians2. The term was added to the Oxford English Dictionary in June 2014 and Merriam-Webster that same spring7. Scrabble also added "hashtag" to its Fifth Edition Official Scrabble Dictionary7.

By the mid-2010s, hashtags had migrated beyond social media entirely. People used them in emails, text messages, and spoken conversation. The word "hashtag" itself became a punchline and cultural shorthand, with Urban Dictionary entries mocking overuse as "the international bat signal for white women"21 and late-night comedians riffing on the absurdity of saying "hashtag" out loud.