For a society, this will have negative impact. I do not mean this project, but in general decentralizing websites and internet contents. Think of all those pedophiles, propagandist. Combine this with subliminal AI and that's your worst nightmare for the society.
From their website:
With Substratum, any member has the ability to vote content up or down. This allows people to identify bad players like child pornography or terrorism and get them removed from the network. This is a truly decentralized internet and the next logical step in our digital journey.
Looks like they have already though about that!