C'est quoi Hubzilla?
Hubzilla est une plate-forme CMS et une alternative Fediverse à Facebook, Dropbox, Google Calendar et bien plus encore.
What does Hubzilla feel like?
Hubzilla can't be compared to other projects but some my take it as as Facebook replacement. It can do everything what Friendica can do since it is a follower up project. So you can do Macrobloging , file sharing, photo sharing, event sharing, chat and more. The key features above Friendica are the identitie functions called "Nomadic identitie", "Open Web Auth" and a sophisticated "Access control" system. Read more about it here: https://joinfediverse.wiki/Hubzilla#Features
Hubzillas's special place in the Fediverse
Hubzilla is part of the Fediverse, so you can't just communicate with other Hubzilla users, but people all over the Fediverse plus some other Networks like e. g. diaspora*. There is also an add-on option for cross posting with a Twitteraccount. Since Hubzilla is like a CMS there are lots of other add-ons you can install for lot of other funktions.
With a Hubzilla web identitie called "channel" and the funktion "Nomadic identitie" channels can be unbound from the hub where they are created. They may be ported to a different hub, but also cloned, in which case the channel's identity and data will exist simultaneously in more than one location.
Also with the funktion "Open Web Auth" it is possible to just access the content of different web sites, without the need to enter usernames and passwords for every site. It is a Single-Click user identification: the ability to access sites simply by clicking on links to remote sites.
With the sophisticated "Access control" System, which allows also groups and forums, you finally can start communicate more private and control exactly who shell see your posts and files.
Further reading
Hubzilla
How do I get an account?
Getting started with your Fediverse account
Best practices
Mobile apps