While it will have a decentralized peer-to-peer network, it probably won't be a blockchain-based system (e.g. it won't contain a financial ledger), although it will likely make use of blockchain-based services at times (any blockchain could theoretically be used, but I expect Hive will be the one most commonly used, because transactions are cheap, it is geared towards storing text information, and HAF should simplify high performance interoperability).