As you will recall, recently Instagram implemented a new feature that would allow IG users to follow hashtags. The following is from @socialcrewmarketing:
On @Twitter, tweets with hashtags get two times more engagement than tweets without.
On @Twitter, when you use more than two hashtags, your engagement drops by an average of 17%.
On @Instagram, interactions are highest with posts that have 11 or more hashtags.
On @Facebook, posts without a hashtag fare better than those with a hashtag.