A hashtag is defined as a useful word or phrase preceded by a hash sign '#'. It is most commonly used on social media sites to link messages or content to the specific word or phrase identified by the hashtag. Hashtags make it possible to group messages or posts linked to the hashtag. The power of a hashtag is in the ability to search for the hashtag and to generate a set of messages or posts that contain the hashtag.
From a marketing perspective the use of hashtags will:
Increase your promotional reach
Amplify your brand or company awareness
Focus your message on your target market
Boost the likelihood of people finding your content
Improve your search engine optimisation results