The hashtag is possibly* the most misunderstood and misused phenomenon of the social media age.
Take a cursory peek at Twitter or Instagram or even Facebook (however post on Facebook with hashtags tend to do worse, than one without hashtags) at any given time of the day or night and you will almost undoubtedly see a selection of posts with hashtags like #feelingtired or #bringonFriday or #yum.
Hashtags, essentially, that have no function. Take the # out and it would make no difference whatsoever to the tweet or post.
Hashtags were invented to group tweets with a similar subject together. Grouping tweets together make it easier for people to find out about something they are interested in. Search #RoyalWedding2018 in Twitter and you will discover what we mean.
Now hashtags have been expanded to include virtually every industry and subject under the sun (try #combineharvesters for example). However the rule, essentially, is this: if no-one else is using the # then adding it won’t benefit your business. When thinking of a hashtag to use, think about what potential customers are searching for.