Creating, updating, and aggregating Web contents from different sources (e.g., Web users and sites) form the core idea of the Web 2.0. However, Web users originate from different communities, and follow their own semantics (referred to as local contexts in this paper) to represent and interpret Web contents. Therefore, several discrepancies could rise up between the semantics of Web authors and readers. In this paper, we present several Web 2.0 scenarios, and illustrate the possible challenges and trends to handle the local contexts of Web users in these scenarios.