Recommender Systems 1 -- Resource Recommendation in Collaborative Tagging Applications -- Combining Collaborative and Content-Based Techniques for Tag Recommendation -- Category Recommendation in User Specified Structure -- Recommender Systems 2 -- Semantic Tag Cloud Generation via DBpedia -- Social Networks as Data Source for Recommendation Systems -- Content-Based News Recommendation -- E-Payment, Security and Trust -- Towards a Lawfully Secure and Privacy Preserving Video Surveillance System -- Reputation as Aggregated Opinions -- The Open Metaverse Currency (OMC) – A Micropayment Framework for Open 3D Virtual Worlds -- T-REX: A Hybrid Agent Trust Model Based on Witness Reputation and Personal Experience -- Service Oriented E-Commerce and Business Processes -- QoS Contract Formation and Evolution -- Process Views to Support Compliance Management in Business Processes -- Invited Talk -- Web Advertising -- Agent-Based Electronic Commerce 1 -- Electronic Trading Environments for Web 3.0 -- Agent-Based Electronic Commerce 2 -- On the Benefits of Keyword Spreading in Sponsored Search Auctions: An Experimental Analysis -- An Optimization Method for Agent’s Bidding Strategy in TAC-SCM Game -- Concession Behaviour in Automated Negotiation -- Bilateral Negotiation in a Multi-agent Supply Chain System -- Recommender Systems 3 -- Receiving Recommendations and Providing Feedback: The User-Experience of a Recommender System -- Comparing Techniques for Preference Relaxation: A Decision Theory Perspective -- Detecting Leaders to Alleviate Latency in Recommender Systems -- Invited Talk -- Electronic Markets, a Look Behind the Curtains: How Can Semantic Matchmaking and Negotiation Boost E-Commerce? -- Recommender Systems 4 -- Quantile Matrix Factorization for Collaborative Filtering -- Partial Ranking of Products for Recommendation Systems.

This book constitutes the refereed proceedings of the 11th International Conference on Electronic Commerce and Web Technologies (EC-Web) held in Bilbao, Spain, in September 2010. The 22 papers accepted for EC-Web, selected from 45 submissions, are organized in topical sessions on recommender systems; e-payment, security and trust; service-oriented e-commerce and business processes; and agent-based e-commerce . The volume is completed by short summaries of the two invited talks on web advertising and electronic markets.