  Understanding the factors that impact the popularity dynamics of social media
can drive the design of effective information services, besides providing
valuable insights to content generators and online advertisers. Taking YouTube
as case study, we analyze how video popularity evolves since upload, extracting
popularity trends that characterize groups of videos. We also analyze the
referrers that lead users to videos, correlating them, features of the video
and early popularity measures with the popularity trend and total observed
popularity the video will experience. Our findings provide fundamental
knowledge about popularity dynamics and its implications for services such as
advertising and search.
