Hashtags are a great tool to use to help improve social media content discovery, but don’t go overboard. Using too many hashtags in a post not only makes it look spammy, but it can also annoy consumers — and that’s the complete opposite of what you are trying to accomplish.
The goal of social media is to build brand awareness, create fans of your brand and then eventually drives sales and revenue. Jamming every post full of every hashtag imaginable will act as customer repellant.
If you use too many hashtags, you will take away from the main message and point of your post, so use them intelligently. Buffer suggests using one to two per post on Twitter is best and that posts on Instagram with 11 or more hashtags receive the best engagement. They also note that Facebook posts with no hashtags outperform posts using hashtags.
Related: 10 Laws of Social Media Marketing