During the last years we are witnessing an ever increasing number of Internet-based marketplaces that capitalize on the unused capacity of assets they already possess, while consumers can receive services from their peers owning assets either for free or at a lower cost. At the same time, the emergence of cryptocurrencies and smart contracts have enabled new distributed application ecosystems, e.g. Ethereum, Hyperledger Fabric, Stellar, Waves, etc., where new services can be deployed with low-entry market barriers, due to minimal infrastructure costs and decentralized and secure transaction management. Innovative business models arise where part of the value generated by these distributed apps is fed back to the distributed blockchain community, as remuneration for their contribution of computational resources. Companies and organizations still require trust: they need to understand their user base, verify identity, manage digital assets, and control trust issuance within their ecosystem. To maximize the market impact of this new economic environment, OntoChain aims to enable trustworthy transactions of services and content. OntoChain will define innovative decentralized reputation models that reveal hidden quality and/or type of providers/services, or credibility of data sources, while adequately balancing the trade-off between privacy and trust. OntoChain will enable trustworthy and traceable content handling where authorized parties can process data according to the privacy policies of the data owners. At the same time, it will build an economically sustainable ecosystem, where the total value generated in the system, in terms of profit or well-being, surpasses the total operational costs in terms of electricity consumption. In order to sustain the user community, OntoChain will aim on fair sharing of the generated value among resource contributors and provide appropriate incentives to the user community for participation.