Introduction to the Special Issue on User-Generated Content in Web3

This editorial introduces the ACM Transactions on Multimedia Computing, Communications, and Applications Special Issue on “User-Generated Content in Web3.” Web3 technologies are reshaping how user-generated content (UGC) is created, assessed, owned, governed, exchanged, and experienced. Effective Web3 UGC ecosystems require technical decentralization, reliable coordination, perceptually grounded evaluation, trustworthy attribution, and careful attention to community and economic dynamics. In this Special Issue, the included eight articles examine this transition from complementary technical and empirical perspectives, spanning decentralized infrastructure and incentive design, collaborative artificial intelligence, dynamic 3D content creation, quality-of-experience (QoE) assessment, content authentication, and the behavior of decentralized communities. Their contributions range from multimedia systems and blockchain to analyses of participation, attention, incentives, and value formation in decentralized networks. Together, they illustrate the opportunities enabled by programmable ownership and open participation and the challenges of trustworthy governance, usable multimedia systems, verifiable provenance, and equitable creator economies.