Blogs are a popular way to share personal journals, discuss matters of public opinion, pursue collaborative conversations, and aggregate content on similar topics. Blogs also disseminate new content and novel ideas to communities of interest. But how does content spread across these communities, what kinds of content spreads, and at what rate? This paper presents an analysis of the network structure and the spreading patterns of media content in the blogosphere. Based on 8.7 million posts in 1.1 million blogs across 15 major blog hosting sites, we show that the network structure of blogs is different from that of other online social networks: most links are unidirectional and the network is sparse. We also find that user generated content, often in the form of videos or photos, is the most common type of content shared in blogs. Focusing on the distribution of 10,000 popularly linked YouTube videos in blogs, we demonstrate how propagation patterns depend on content category. For example, the latest political news video immediately catches the attention of bloggers and fades away after a week, while a music video propagates slowly over a long period of time.