#Hashtags are used to organize records around a common theme. For example, I use hashtag to tweet about all the new features and functionalities in a Salesforce Release ( e.g. #SalesforceWinter20).
You can also use #hashtag in Salesforce with chatter posts and records. Let’s say that you want to capture the hobbies/interests (like ‘Golf’, ‘Soccer’, ‘Investment’, ‘Philanthropy’ etc) of your of leads and contacts. One way to capture this information is to use picklist or multi-select picklist field, which an admin will need to create and maintain. But an easier and better way to capture this information will be to use #hashtags. You can use as many hashtags as you want on a record and then search for information based on that. More