Hashtags are particularly useful in unmoderated forums that lack a formal
ontological organization. Hashtags help users find content similar interest. Hashtags are neither registered nor controlled by any one user or group of users. They do not contain any set definitions, meaning that a single hashtag can be used for any number of purposes, and that the accepted meaning of a hashtag can change with time. Hashtags intended for discussion of a particular event tend to use an obscure wording to avoid being caught up with generic conversations on similar subjects, such as a cake festival using #cakefestival rather than simply #cake. However, this can also make it difficult for topics to become "trending topics" because people often use different spelling or words to refer to the same topic. For topics to trend, there must be a consensus, whether silent or stated, that the hashtag refers to that specific topic. Hashtags may be used informally to express context around a given message, with no intent to categorize the message for later searching, sharing, or other reasons. Hashtags may thus serve as a reflexive meta-commentary. This can help express contextual cues or offer more depth to the information or message that appears with the hashtag. "My arms are getting darker by the minute. #toomuchfaketan". Another function of the hashtag can be used to express personal feelings and emotions. For example, with "It's Monday!! #excited #sarcasm" in which the adjectives are directly indicating the emotions of the speaker. Verbal use of the word
hashtag is sometimes used in informal conversations. Use may be humorous, such as "I'm hashtag confused!"
Co-optation by other industries Companies, businesses, and advocacy organizations have taken advantage of hashtag-based discussions for promotion of their products, services or campaigns. In the early 2010s, some
television broadcasters began to employ hashtags related to programs in
digital on-screen graphics, to encourage viewers to participate in a
backchannel of discussion via social media prior to, during, or after the program.
Television commercials have sometimes contained hashtags for similar purposes. The increased usage of hashtags as brand promotion devices has been compared to the promotion of branded "
keywords" by
AOL in the late 1990s and early 2000s, as such keywords were also promoted at the end of television commercials and series episodes. Organized real-world events have used hashtags and ad hoc lists for discussion and promotion among participants. Hashtags are used as beacons by event participants to find each other, both on Twitter and, in many cases, during actual physical events. Since the 2012–13 season, the
NBA has allowed fans to vote players in as All-Star Game starters on Twitter and Facebook using #NBAVOTE. Hashtag-centered biomedical Twitter campaigns have shown to increase the reach, promotion, and visibility of healthcare-related open innovation platforms.
Non-commercial use promoting the hashtag #OccupyForRights Political protests and campaigns in the early 2010s, such as
#OccupyWallStreet and
#LibyaFeb17, have been organized around hashtags or have made extensive usage of hashtags for the promotion of discussion. Hashtags are frequently employed to either show support or opposition towards political figures. For example, the hashtag
#MakeAmericaGreatAgain signifies support for Trump, whereas
#DisinfectantDonnie expresses ridicule of Trump. Hashtags have also been used to promote official events; the
Finnish Ministry of Foreign Affairs officially titled the
2018 Russia–United States Summit as the "#HELSINKI2018 Meeting". Hashtags have been used to gather customer criticism of large companies. In January 2012,
McDonald's created the #McDStories hashtag so that customers could share positive experiences about the restaurant chain, but the marketing effort was cancelled after two hours when critical tweets outnumbered praising ones. In 2017, the
#MeToo hashtag became viral in response to the sexual harassment accusations against
Harvey Weinstein. The use of this hashtag can be considered part of
hashtag activism, spreading awareness across eighty-five different countries with more than seventeen million Tweets using the hashtag #MeToo. This hashtag was not only used to spread awareness of accusations regarding Harvey Weinstein but allowed different women to share their experiences of
sexual violence. Using this hashtag birthed multiple different hashtags in connection to #MeToo to encourage more women to share their stories, resulting in further spread of the phenomenon of hashtag activism. The use of hashtags, especially, in this case, allowed for better and easier access to search for content related to this social media movement.
Sentiment analysis The use of hashtags also reveals what feelings or sentiment an author attaches to a statement. This can range from the obvious, where a hashtag directly describes the state of mind, to the less obvious. For example, words in hashtags are the strongest
predictor of whether or not a statement is
sarcastic—a difficult
AI problem.
Professional development and education Hashtags play an important role for employees and students in professional fields and education. In industry, individuals' engagement with a hashtags can provide opportunities for them develop and gain some professional knowledge in their fields. In education, research on language teachers who engaged in the #MFLtwitterati hashtag demonstrates the uses of hashtags for creating community and sharing teaching resources. The majority of participants reported positive impact on their teaching strategies as inspired by many ideas shared by different individuals in the Hashtag. Emerging research in communication and learning demonstrates how hashtag practices influence the teaching and development of students. An analysis of eight studies examined the use of hashtags in K–12 classrooms and found significant results. These results indicated that hashtags assisted students in voicing their opinions. In addition, hashtags also helped students understand self-organisation and the concept of space beyond place. Related research demonstrated how high school students engagement with hashtag communication practices allowed them to develop story telling skills and cultural awareness. For young people at risk of poverty and social exclusion during the
COVID-19 pandemic,
Instagram hashtags were shown in a 2022 article to foster scientific education and promote remote learning. == In popular culture ==