Twitter hashtags are a way for Twitter users to include a notation that allows their posted messages to be categorized based on the hashtags they use. These typically consist of a hash mark “#” followed by a particular word or phrase, such as “#wisegeek” to create a hashtag. Such hashtags are created by Twitter users, not by the Twitter service itself, and evolved organically as a desire by users to more easily categorize their posts. Twitter hashtags can be used to more easily search for posts related to a particular subject or to create trends or Internet memes by utilizing certain hashtags.
The structure of Twitter hashtags is quite simple, and consists of a hash mark followed by a phrase or word chosen by a Twitter user. These hashtags are part of the 140 character maximum allowance afforded by Twitter, and so care is typically used in creating these tags. Most Twitter users frown on the use of hashtag spam, which consists of more than three hashtags used within a single post. Twitter hashtags can consist of anything from celebrity gossip that might consist of “#celebrityname” to news about a natural disaster using a hashtag like “#disaster.”
Since Twitter hashtags are created by Twitter users, there is no particular way in which such hashtags are created other than by simply using them. Someone interested in creating a new hashtag merely has to use it in a Twitter post, after which it exists as an established hashtag. As other users, usually followers of the first poster, see this hashtag, they can use it as well and create a group of posts that all use the same tag. Other users can then search for Twitter hashtags specifically, rather than just a subject, to find only those posts that used the hashtags.
A group of people interested in collecting antique swords might begin using Twitter hashtags for posts made about swords for sale such as “#antiquesword” or “#oldsword.” Other users could then search for that hashtag to find those posts offering such swords for sale, and more easily connect with sellers. Twitter hashtags can also be used to help people communicate in times of difficulty, or for social satire and political commentary. People in a natural disaster can use hashtags to quickly and effectively update others on conditions at the site of the disaster, while political commentators can use hashtags to quickly point out logical errors or mistakes made by politicians by using those mistakes as a hashtag.