Hashtag
Also known as: Hash tag · pound sign tag · # tag
A hashtag is a word or phrase prefixed with the # symbol, used on social media to tag and organize posts around a shared topic. First proposed for Twitter by Chris Messina on August 23, 20071, the hashtag grew from a niche convention into one of the most recognizable features of online communication, eventually being named the 2012 Word of the Year by the American Dialect Society2.
Overview
A hashtag is a metadata label consisting of the # symbol followed by a word or phrase with no spaces. When someone includes a hashtag in a post, it groups that content with every other post using the same tag, making it easy to find and follow conversations about a specific subject3. The format is dead simple: type #, add your keyword, and you've created a searchable link to a broader discussion.
Hashtags are not case-sensitive (#Hashtag and #hashtag return the same results), though CamelCase improves readability3. The convention works across nearly every major social platform today, from X (formerly Twitter) and Instagram to Facebook, YouTube, TikTok, and LinkedIn5.
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.
Origin & Background
How It Spread
How to Use This Meme
Hashtags follow a simple format:
Type the # symbol followed immediately by your word or phrase (no space between # and the word)
No spaces or special characters within the hashtag. Multiple words run together: #ThrowbackThursday, not #Throwback Thursday
Keep it concise. #bizducks works better than #businessofthecallingducksconference
Give context. If creating a new hashtag, explain what it's for in your first few posts
Cultural Impact
Full History
Fun Facts
Twitter co-founder Ev Williams initially dismissed Messina's hashtag proposal, saying it was too "geeky" for mainstream users
The # symbol's technical name is "octothorpe," coined at Bell Labs in the 1960s. The "octo" refers to its eight points, and "thorpe" may honor Olympic athlete Jim Thorpe, though the exact etymology is debated
Chris Messina graduated from Carnegie Mellon University with a communication design degree in 2003, four years before proposing the hashtag
The #AmazonFail hashtag in April 2009 was one of the first examples of collective Twitter outrage, and Clay Shirky's analysis of it became a widely cited essay on how social media can short-circuit critical thinking
In Singapore and Malaysia, the # symbol is commonly called "hex" and is used in apartment addresses to indicate floor numbers
Derivatives & Variations
Hashtag activism / #hashtag movements:
The use of hashtags to organize political and social campaigns (#BlackLivesMatter, #MeToo, #JeSuisCharlie, #IceBucketChallenge)[5]
Hashflags:
Twitter's custom implementation that replaces certain hashtags with small icons or national flags, first deployed during the 2010 World Cup[3]
Cashtags ($):
StockTwits adapted the hashtag concept in 2009 using $ instead of # to tag ticker symbols for stock market discussion[3]
Trending Topics:
Twitter's real-time display of popular hashtags, introduced in 2010 and later monetized through sponsored trends[18]
#GNO (Girls' Night Out):
A weekly Tuesday-night Twitter party started by mommy bloggers in 2008 that ran for years with hundreds of participants each week[11]
Hashtag memes for counter-narrative:
Communities using hashtags to challenge media coverage, including #TweetLikeAForeignJournalist, #UgandaIsNotSpain, and #Ottawapiskat[20]
Frequently Asked Questions
References (22)
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- 4Hashtag - Know Your Memeencyclopedia
- 5Hashtagencyclopedia
- 6Hashtag - Urban Dictionarydictionary
- 7October 2007 California wildfiresencyclopedia
- 8Number sign - Wikipediaencyclopedia
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