In this work we propose intelligent, automated content analysis techniques for different media to extract knowledge from the multimedia content. Information derived from different sources/modalities will be analyzed and fused, in terms of spatiotemporal, personal and even social contextual information. In order to achieve this goal, semantic analysis will be applied to the content items, taking into account the content itself (e.g. text, images and video), as well as existing personal, social and contextual information (e.g. semantic and machine-processable metadata and tags). The above process exploits the so-called ``Media Intelligence'' towards the ultimate goal of identifying ``Collective Intelligence'', emerging from the collaboration and competition among people, empowering innovative services and user interactions. The utilization of ``Media Intelligence'' constitutes a departure from traditional methods for information sharing, since semantic multimedia analysis has to fuse information from both the content itself and the social context, while at the same time the social dynamics have to be taken into account. Such intelligence provides added-value to the available multimedia content and renders existing procedures and research efforts more efficient.