I just finished a paper that looked at technology, music, and protest. Social networks and mining play lists was part of the lit review. I think they are likely related.. Some resources.

Malcolm, S., & William, W. (2006). Measuring playlist diversity for recommendation systems. Paper presented at the Proceedings of the 1st ACM workshop on Audio and music computing multimedia.

Cheng, Y. (2003). Peer-to-peer architecture for content-based music retrieval on acoustic data. Paper presented at the Proceedings of the 12th international conference on World Wide Web, Budapest, Hungary.

Ahn, Y.-Y., Han, S., Kwak, H., Moon, S., & Jeong, H. (2007). Analysis of topological characteristics of huge online social networking services. Paper presented at the The 16th international conference on World Wide Web, Banff, Alberta, Canada.

Bockstedt, J. C., Kauffman, R. J., & Riggins, F. J. (2006). The Move to Artist-Led On-Line Music Distribution: A Theory-Based Assessment and Prospects for Structural Changes in the Digital Music Market. International Journal of Electronic Commerce, 10(3), 7-38.