Hubzilla
Hubzilla is a powerful platform for creating interconnected websites featuring a decentralized identity, communications, and permissions framework built using common webserver technology.
20 Alternatives To Hubzilla
HumHub
HumHub is a free social network software and framework built to give you the tools to make teamwork easy and successful.
Mastodon
Mastodon is a decentralized, open source social network. This is just one part of the network, run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome!
WordPress
WordPress is web software you can use to create a beautiful website or blog. We like to say that WordPress is both free and priceless at the same time. Extend WordPress with over 55,000 plugins to help your website meet your needs.