The hashtag (from hash "hash" and tag "label") is a type of tag used on social networks (Instagram, Facebook, Twitter) as a thematic aggregator. It is different from the simple tag, indicated by the @ symbol and used to link to a user’s contact or profile page.
Hashtags make it easy to find photos and content related to a specific topic or category. To create a hashtag, enter the # symbol followed by a word or phrase without spaces.
Content shared on social networks using hashtags gains more visibility and authority online, making it easier for users to be found and increasing likes, followers, and interactions.
Here are the Best Instagram Hashtags 2017 to get lots of followers and likes