Abstract

The hashtag, a phrase that is highlighted by preceding it with a hash symbol (#), is already 6 years old. People use it on a massive scale in social media, with two objectives: to tag (or label) conversations and content, and to identify communities. It can be used also as a rhetorical element in activism, marketing, or just for amusement. Recent research highlights its value as a predictive system and for engaging the TV audience using Twitter. Some national and academic libraries are storing and preserving hashtags for future research.