http://awuuwa.i2p/webpages/Fediverse%20vs%20Retroshare.html
In a friend-to-friend network the node in the middle merely passes the information on, it is not responsible for managing the information at all in any way. The only real difference between a fediverse server and any contemporary "big tech" platform, is the fact that anyone can create their own server instance, and they can exchange information like on email with other server instances.