The article describes the why (Facebook etc.) and what (FreedomBox[1]) but I don't think it's immediately clear how "cheap, small, low-power plug servers" circumvent tracking unless you already knew about FreedomBox.
From the FAQ[2]: "FreedomBox allows you to provide services to your family and friends (files and bookmarks hosting, remote storage, chat, wiki/blog), to protect your private life against advertising companies while surfing on the net, and to stay anonymous on the network."
From the FAQ[2]: "FreedomBox allows you to provide services to your family and friends (files and bookmarks hosting, remote storage, chat, wiki/blog), to protect your private life against advertising companies while surfing on the net, and to stay anonymous on the network."
[1]: https://freedombox.org/
[2]: https://wiki.debian.org/FreedomBox/QuestionsAndAnswers#What_...