RetroShare Multi-Distribution Repositoryhttps://retroshare.cc/
RetroShare establish encrypted connections between you and your friends to create a network of computers, and provides various distributed services on top of it such as forums, channels, mail, etc.
RetroShare is fully decentralized, and designed to provide security and anonymity to its users. RetroShare is is entirely free and open-source software.
It is available on Windows, MacOS, FreeBSD and most GNU/Linux distributions. There are no hidden costs, no ads and no Terms of Service.