  We examine the growth, survival, and context of 256 novel hashtags during the
2012 U.S. presidential debates. Our analysis reveals the trajectories of
hashtag use fall into two distinct classes: "winners" that emerge more quickly
and are sustained for longer periods of time than other "also-rans" hashtags.
We propose a "conversational vibrancy" framework to capture dynamics of
hashtags based on their topicality, interactivity, diversity, and prominence.
Statistical analyses of the growth and persistence of hashtags reveal novel
relationships between features of this framework and the relative success of
hashtags. Specifically, retweets always contribute to faster hashtag adoption,
replies extend the life of "winners" while having no effect on "also-rans."
This is the first study on the lifecycle of hashtag adoption and use in
response to purely exogenous shocks. We draw on theories of uses and
gratification, organizational ecology, and language evolution to discuss these
findings and their implications for understanding social influence and
collective action in social media more generally.
