A hashtag is a pound sign or hash mark (#) followed by a word or phrase that is used on many social media platforms to annotate posts, allowing them to be organized and searched by platform users. Additionally, hashtags have metacommunicative functions that can be used to extend the content of the post. For example, hashtags can be employed by platform users to convey emotion about the subject of the post; reflect on the poster’s mood or condition; mark the post as a reference to and extension of a large-scale body of social content, such as a well-known Internet meme, popular cultural reference, or fan community “inside joke”; provide critique or commentary; convey irony; identify social affiliation; and participate in collaborative social activities, such as ...