In this paper, we propose a real-time and collaborative hyper-media system that introduces database-enhanced collaborative models and multimedia processing models for creating improvised performances in the Opera of Meaning. The system provides a main story media and a corresponding shared canvas that is shared among Internet-wide user communities. Our shared canvas mechanisms make it possible to describe and share users' ideas and impressions about the main story media. The key technology of this system is a timeline-dependent and script-driven live performance engine, which provides users with ECA rules to express and characterize the users' ideas and impressions by using existing multimedia data such as video files and image files. The system provides directors and participants of improvised performance with a set of database operators for controlling and contributing to the performance. The system motivates users to contribute to the performance by exploiting users' own media libraries and existing web services. We have implemented the prototype system which is applicable to the existing video and image files on the Web.