It becomes more and more clear to me that there are two seminal books now in the field of online communications: Convergence Culture, by Henry Jenkins, and The Wealth of Networks, by Yochai Benkler (online). Just those. Everything else is either old or derivative.
Yes, I’m being deliberately provocative with that last remark. As I tried to come up with other books to mention in this post, however, I rejected each and every one that came to mind.