  Today's Internet traffic is mostly dominated by multimedia content and the
prediction is that this trend will intensify in the future. Therefore, main
Internet players, such as ISPs, content delivery platforms (e.g. Youtube,
Bitorrent, Netflix, etc) or CDN operators, need to understand the evolution of
multimedia content availability and popularity in order to adapt their
infrastructures and resources to satisfy clients requirements while they
minimize their costs. This paper presents a thorough analysis on the evolution
of multimedia content available in BitTorrent. Specifically, we analyze the
evolution of four relevant metrics across different content categories: content
availability, content popularity, content size and user's feedback. To this end
we leverage a large-scale dataset formed by 4 snapshots collected from the most
popular BitTorrent portal, namely The Pirate Bay, between Nov. 2009 and Feb.
2012. Overall our dataset is formed by more than 160k content that attracted
more than 185M of download sessions.
