Salut à Toi is Libre (free as in freedom), that means that it follow the free software philosophy, not only because it's the best way to develop a software, but also for the share and freedom spirit.
In addition, Salut à Toi follow a social contract: a moral engagment with the user.
By being based on XMPP
SàT is naturally decentralised. That mean that there is not one big server somewhere where all the data are staying. That's the only good way to fight against censorship, and to keep control of your data (you don't want to have your private pictures or intimate messages to be in the hands of an untrusted commercial company, do you ?).
Using a standard protocol is a key point: it's robust, widely used and tested, well documented. Every change is discussed publicly, there are debates on the best way to do things, and the XSF
is the guarantor of the evolution and stability of the protocol. That means that SàT can communicate easily with other XMPP
projects: the way it "talk" to others is fully documented.
Federation means that SàT is open to the world: it can communicate on the global Jabber network. You can of course make your own private network if you wants, but with SàT you have the ability to send messages to somebody on an other server, using a different client. That's at the opposite of some proprietary and commercial networks which tend to lock their users up. Open your borders !