Ethos is designed such that all interactions in the protocol are stored onchain. This ensures that anyone can read and write reviews, vouches, slashes, etc. to the protocol.
Reviews, vouches, slashes, attestations (social connections), invitations, voting and commenting (discussions) are all stored onchain in the various Ethos smart contracts.
If you ever want to quickly see the current smart contract addresses, you can hit cmd + shift + e in the Ethos webapp for quick links to the contracts.
Due to the complexity and ever changing requirements of the Ethos credibility score, we are currently not storing scores onchain for each user. However, we have plans to slowly migrate to a model where the calculated results are stored onchain, while the calculations themselves are handled by oracles.
Our goal is for all Ethos data to be stored onchain so that others can observe and extend this data.
The Ethos webapp is simply an interface for the smart contract protocol.