Excessively Tagging On Instagram Shown To Increases Likes
Instagram photos which have the maximum of 30 #tags receive, on average, about three times as many Likes than photos with only a few tags. Most of the averages are well-bounded, too, which indicate that the per-tag-Like-averages are well-representative of all Instagram photos.
A comparison between Twitter and Instagram would be interesting here. I don’t think you would see the same correlation on Twitter between number of tags and number of interactions. In fact, Twitter recommends that you do not use hashtags or mentions if you are trying to maximise conversion rates on links inside a tweet.