The rapid evolution of Internet technologies have witnessed new Web elements, such as blogs, wikis, social networking, social bookmarking, and other related applications referred to as Web 2.0. Web 1.0 paradigm was related with passive, just receptive users, whereas Web 2.0 paradigm relies mainly on user participation and user-generated content. In Web 2.0 applications users are invited to comment, share, edit, classify, as well as remix data from multiple sources. Although there are several Web 2.0 applications in the market there is still lack of a profound approach guiding the analysis, design and development of such applications. This paper suggests classifying Web 2.0 tools by “Pattern of Usage” or in other words the functionalities that characterize their specific features. By reviewing several literatures we extracted multiple attributes related to functionalities of Web 2.0 tools. These have been crystallised into 7 patterns of usage that include; Inter-connectivity, Content authoring, Content tagging & rating, Content aggregation & syndication, Content remixing, Content streaming and File sharing. By interlinking functionality/ usage with underlying technologies, techniques and architecture we provided insight into design and technical requirements for Web 2.0 supported applications. Furthermore we broke down the patterns into basic, elementary to include Inter-connectivity, File sharing and Content remixing, and secondary, supportive to include the other four patterns. This would provide the technical core for any development methodology targeted at Web 2.0 applications.