So far, data-centers have demonstrated to be scalable and dependable. In this context, the interest for peer-to-peer systems declines. Immediately, the main conferences dealing with peer-to-peer have claimed to be open to submissions of papers being not totally distributed: it is the time of peer-assisted architectures, and overlays of devices controlled by a central authority (e.g. set-top-boxes). See for example this paragraph in the Call for Papers of the ninth workshop on Peer-to-Peer Systems (IPTPS 2010)
"This year, the workshop's charter will be expanded to include topics relating to self-organizing and self-managing distributed systems. This is in response to recent trends where self-organizing techniques proposed in early peer-to-peer systems have found their way into more managed settings such as datacenters, enterprises, and ISPs to help deal with growing scale, complexity, and heterogeneity. In the context of this year's workshop, peer-to-peer systems are defined to be large-scale distributed systems that are mostly decentralized, are self-organizing, and might or might not include resources from multiple administrative domains."
Another consequence is that the only area where peer-to-peer experts can reasonably argue that pure peer-to-peer systems make sense -- live streaming systems -- has received an dramatic attention fueled by tons of grants: more than seven thousands papers containing the words peer-to-peer, live and streaming have been published since 2009. From an algorithmic perspective, the similarities between pure peer-to-peer and Content-Centric Networking make that this latter is becoming a hot topic among the peer-to-peer experts. To my opinion, the gap between this sudden peak of scientific works and the need for research in these areas is huge.
But, what about the research about fully decentralized peer-to-peer architecture for free systems? The troubles around Wikileaks, the recurrent funding issues faced by free services like wikipedia or arXiv, and the terrible privacy problems of current social platforms should invite every reviewer (not only in conferences but also in funding agencies) to consider the "free systems" motivation as critical.