What is hashtag?
Hashtag
A keyword prefixed with # that groups a post into a searchable feed alongside every other post using it.
Hashtags do two jobs that get confused. A broad tag is a distribution attempt, usually a poor one, since the feed moves too fast to be seen. A branded tag is a collection mechanism, and it works: it gives customers a place to file their posts and gives the brand a way to find them.
Branded tags are worth owning explicitly, because an unclaimed one gets used for something else.