An excellent post from my good friend Gordon Brander: Decentralizability
It points out that if you decentralize a system from the beginning makes it significantly harder to evolve, and might prevent you from actually making a product with PMF.
The right approach is to have minimum viable decentralization to start, and then grow from there.
The three components to meet the decentralizable bar:
Publish immutable data
Use universal identifiers
Sign everything with user-controlled keys