Trust is essential to societies, and blockchain has the potential to shift trust in people and institutions to trust in technology. This view is in line with the recent emergence of less centralised paradigms for trust, that can offer concepts and techniques for efficiently operating large volumes of socially connected subjects, for example, peer-to-peer networking and the move from institutional and intermediary trust to modern era decentralised trust relying on technology. Decentralised architectures are much more appropriate for clustering subjects (users) and objects (e.g. media items) into communities and for maintaining social relationships. It is the main vision of the TreBlo project to nurture and facilitate beyond the state-of-the-art research on blockchain technology which will lead to more scalable blockchain based solutions and applications. The latter will contribute to ensuring the exchange of trustworthy and reliable content on social networks and media. To achieve this, the project will implement a series of open calls that will target academic and R&D companies research teams. They are invited to define and implement small scale research projects on two related use cases, obtaining technical and business support services from TreBlo: - Use case 1: Trust and reputation models on blockchains. This targets innovative applications, technologies, technical approaches and methodologies that increase the levels of trust in blockchain-based information exchange, with emphasis on user generated content on the Internet and social media, considering also data from IoT infrastructures. - Use case 2: Proof-of-validity and proof-of-location. The focus is on innovative mechanisms to increase transparency and trustworthiness of user generated genuine content. The users, as being part of a blockchain, can apply additional verification mechanisms to increase transparency, validity and high level of trustworthiness, such as Proof- of-Location and Proof-of Validity.