—The recent three years have witnessed an explosion of networked video sharing, represented by YouTube, as a new killer Internet application. Their sustainable development however is severely hindered by the intrinsic limit of their client/server architecture. A shift to the peer-to-peer paradigm has been widely suggested with success already shown in live video streaming and movie-on-demand. Unfortunately, our latest measurement demonstrates that short video clips exhibit drastically different statistics, which would simply render these existing solutions suboptimal, if not entirely inapplicable. Our long-term measurement over five million YouTube videos, on the other hand, reveal interesting social networks with strong clustering among the videos, thus opening new opportunities to explore. In this paper, we present NetTube, a novel peer-topeer assisted delivering framework that explores the clustering in social networks for short video sharing. We address a series of key design is...