Here are some quick research notes I have from earlier P2P browsing.

GNUnet acts as the decentralized platform, PSYC2 handles protocols across that, and secure share implements PSYC2 for some actual use-cases.

Worth a look if you're into P2P tech.

 GNUnet

Website: gnunet.org

GNUnet is a mesh routing layer for end-to-end encrypted networking and a framework for distributed applications designed to replace the old insecure Internet protocol stack.

In other words, GNUnet provides a strong foundation of free software for a global, distributed network that provides security and privacy. Along with an application for secure publication of files, it has grown to include all kinds of basic applications for the foundation of a GNU internet. 

 PSYC2

Website: about.psyc.eu
PSYC2: about.psyc.eu/PSYC2
White Paper: psyc.eu/whitepaper

 PSYC is a flexible protocol to set up a worldwide distributed messaging infrastructure mostly for text-based conferencing (popularly termed chatting). It was developed with the goal in mind to replace the Internet Relay Chat protocol, which has reached its limits.

 The new approach instead uses a hybrid strategy of pseudonymous peer-to-peer routing combined with helpful dumb servers. The intention is to arrive at an unheard degree of privacy, far beyond the usual PGP and OTR installations. The new stack, based onlibpsyc, also uses a new protocol syntax, renewed for efficiency. The secure share project is our prototype platform for the new PSYC. We call it PSYC2. 

 secure share

Website: secushare.org
Article: 15 Reasons not to start using PGP

Think of Facebook, Whatsapp, Gmail and Skype rolled into one, without the centralized surveillance and control.

secushare employs GNUnet for end-to-end encryption and anonymizing mesh routing (because it has a more suitable architecture than Tor or I2P) and applies PSYC on top (because it performs better than XMPP, JSON or OStatus) to create a distributed social graph. Together, these technologies allow for distributed private social networking including more straightforward and secure e-mail, chat, exchange of content and a private web.

It's even a safer choice for the Internet of Things.