Decentralization is a significant technical and philosophical topic. There are lots of really interesting decentral technologies showing up. It's also a concept discussed in politics and social philosophy. It seems to me it deserves a stackexchange site.
There are many extant decentral technologies now that people may have technical questions about. There's also active development happening so I envision some discussion about technical points of eg meshnet protocols. Many people have a strong philosophical affinity for decentral patterns of human activity; I think the site would nicely embrace discussion of finer points and controversies of decentral social patterns.
Some examples of specific applications below.