Hashtags are a way for Twitterers to categorize their tweets by topic. Hashtags basically serve as a label, allowing other people to search on Twitter and quickly find tweets relating to a given subject.
Making tweets with common topics searchable is the key purpose of hashtags. It's basically a user convention, an ad hoc way of organizing tweets. With so many different words available to label any given topic, the hashtag (#) convention is designed to get everyone who is talking about a common subject to agree to use the same keyword in their tweets.
Hashtags can be placed anywhere in a tweet--beginning, middle or end. To create a hashtag, just place the # symbol in front of a keyword in your tweet, such as "Going to #Oriolesgame tomorrow."
Twitter Hashtags HistoryHashtag is a mashup of "hash" and "tag." Hash refers to the # symbol, often known as a hash symbol. "Tag" is computer system lingo referring to a keyword or term assigned to a particular piece of information to describe it and allow it to be found through searching.
Twitter users invented hashtags as a way to organize their tweets. Twitter makes hashtags clickable so that when a hashtag is clicked on, all the other tweets that include that hashtag appear in a timeline.
But Twitter does not officially assign or create hashtags for any topics or events. Users do that.
Something similar to hashtags previously had been used in IRC (Internet Relay Chat) years earlier, which may have contributed to the initial idea of using them on Twitter.
First Twitter Hashtag: #Barcamp
Entrepreneur Chris Messina was the one who initially proposed the use of Twitter hashtags in 2007. The first time they were actually used on Twitter related to conversation about a "barcamp" conference that year.
GigaOm reported that the very first hashtag was placed in a tweet on Aug. 23, 2007. The tweet said, “how do you feel about using # (pound) for groups. As in #barcamp [msg]?”
Hashtags started catching on with other Twitter users later in 2007 during the San Diego forest fires, when a Twitter user put #sandiegofire into his tweets. Hashtags since have become extremely popular for organizing tweets about live or real-time events.
Variations of Twitter Hashtags
Hashtag is also sometimes spelled as two words -- hash tag.
Some people call them simply "tags" or "Twitter tags."
Since hashtags are basically keywords with the # in front, other people consider them the same thing as a "keyword."
Using Hashtags on TwitterUsing hashtags on Twitter is a popular, easy way to create live, searchable dialogues at conferences and other live events (#eventname.) Another popular way people use them is for tracking shared interests, such as #skydiving. Still others use them for group chats, by designating members of group having a conversation #werewolveguys.
Twitter users frown on people overusing hashtags or using them for topics that are not really related to the keyword they contain. Overusing hashtags means putting too many in a single tweet, which looks ugly and can be considered spam. More than three tags in one tweet is considered excessive.
Hashtags have evolved and are often use for commentary, sometimes satirical or funny. The New Yorker published a witty online article about the multiple layers of using hashtags.
Tracking Hashtags on Twitter: Resources for Finding Hashtags
Twitter has an official hashtag user account created for tracking the tags at twitter.com/hashtags. People used to have to "follow" this account on Twitter in order for it to index their hashtags. But Twitter has since automated the tracking of hashtags, which are now searchable at the main Twitter search page.
Several independent sites track hashtags on Twitter and make them searchable, including hashtag.org.
Each hashtag has its own RSS feed with a URL or Web address at hashtag.org. If the hashtag is #wildhats, then the feed will be http://hashtags.org/feeds/tag/wildhats.Other sites serve as dictionaries for hashtags and aggregate them, such as Twemes.com, which shows popular tags.
Twubs and Tagalus (URL: tagal.us) also list hashtags and provide information on when and how they are used.
This article reviews more tools for tracking and using hashtags on Twitter.
Pros and Cons of Twitter Hashtags
The main pro of putting a #hashtag in your tweet is making it findable to people following that topic or tag. The main con is that the #hashtag takes up some of your precious 140 characters.
Read more about more tweeting terms in the Twitter Language guide.