The Hashtag
A reader's summary of the humble pound sign that became the internet's way of saying “this post belongs with those,” and of what that small convention did to how crowds form online.
The term at a glance
A hashtag is a word or phrase preceded by the # symbol that marks a post as part of a topic, so that readers can click or search it and see every other post carrying the same tag. It is a user-made index: no editor assigns the categories, and anyone can start a new one by simply using it. It is related to, but different from, the folksonomy-style tags of earlier sites like Flickr and Delicious, in that a hashtag sits inside the text of the message itself and is meant to be read as part of the sentence.
Origin
The # sign had been used for channel names on IRC chat for years before Twitter existed. On August 23, 2007, the product designer Chris Messina posted a message asking how people felt about using the pound sign to group conversations, with the example “#barcamp,” a reference to the unconference events he helped organize. Twitter had no search feature built around it at the time, and the reaction from the company is usually remembered as unenthusiastic. Messina has said he chose not to patent the idea. The word “hashtag” itself is generally credited to the writer Stowe Boyd, who used it in 2008.
History and context
The convention found its first widely cited use in October 2007, when wildfires burned around San Diego and a local user, Nate Ridder, posted updates under #sandiegofire so residents could follow the situation in one place. Twitter added search to the site in 2009 and, in the same year, began turning hashtags into clickable links and listing the most used ones as trending topics, which converted a user habit into a platform feature. The tag then moved from event coordination to political organizing: #BlackLivesMatter appeared in 2013 after the acquittal of George Zimmerman, and in October 2017 the actor Alyssa Milano asked people to reply “me too” to draw attention to harassment, reviving the phrase Tarana Burke had used for her own work since 2006. The Oxford English Dictionary added the word in 2014. The same mechanism is behind the critique in slacktivism, the way tags can be gamed in a brigade, and the question of whether a topic is surfaced or buried that comes up in shadowbanning.
Main ideas
A tag is a cheap, shared meeting point
Before hashtags, finding everyone talking about one event meant knowing whom to follow. A tag lets strangers who have never heard of each other land in the same stream by typing the same few characters. Nobody has to approve it, register it or run it.
Convention came first and software followed
Users adopted the symbol, and the platform later made it clickable and searchable. That order matters: the habit proved there was demand, and the product feature then locked it in. Instagram and others copied the feature, so a tag now works across most major networks.
A tag turns scattered posts into a visible crowd
Once a tag is trending, the count itself becomes a signal that something is happening. That is why a hashtag can bring attention to an event or a grievance quickly, and also why the attention can be bought, staged or hijacked.
The label belongs to no one
Because anyone may attach it, a tag cannot carry a single meaning. Campaigners, brands, jokers and spammers can all use the same string, and the original users have no tool to keep it on topic. The meaning ends up being whatever the loudest posters make it.
It organizes attention, not truth
A tag groups posts by topic and says nothing about whether they are accurate, representative or written by real people. A trending tag is a count of recent posts, so it is exactly as reliable as the accounts producing them.
Critique
- Visibility is not the same as change. A tag can put a cause in front of millions of people, but whether it leads to anything beyond attention depends on organizing that happens off the platform. Researchers who study protest movements generally treat a tag as a way to gather people and a poor substitute for what they do next.
- Tags are easy to hijack. Opponents or marketers can flood a popular tag with unrelated or hostile posts until the original users cannot find one another, which has happened to corporate campaigns that invited the public to share and received mockery.
- The habit degrades the writing. Stacking tags at the end of a post to chase reach, or inserting them mid-sentence, can make text harder to read. Platforms have also shifted toward recommendation by algorithm, so tags matter less for discovery than they once did, even as people keep using them out of habit.
Impact
The hashtag showed that a platform can get a lot of structure from a convention that costs users one keystroke. It also set the pattern for how online attention is counted: a trending list is a public scoreboard, and anything with a scoreboard attracts people who want to move the score. A sensible way to read a trending tag is to ask who started it, whether the posts under it come from varied accounts or a few repeating ones, and what happened after the count peaked.