We present the design of Plurality,1 an interactive tagging system. Plurality's modular architecture allows users to automatically generate high-quality tags over Web content, as well as over archival and personal content typically beyond the reach of existing Web 2.0 social tagging systems. Three of the salient features of Plurality are: (i) its self-learning and feedback-sensitive capabilities based on a user's personalized tagging style; (ii) its leveraging of the collective intelligence of existing social tagging services; and (iii) its context-awareness for optimizing tag suggestions, e.g., based on spatial or temporal features. Categories and Subject Descriptors: H.3.1 Information Storage and Retrieval: Content Analysis and Indexing General Terms: Algorithms, Design