In this era of Web 2.0, much information is available on the Internet. Software forums, mailing lists, and question-and-answer sites contain lots of technical information. Blogs contain developers’ opinions, ideas, and descriptions of their day-to-day activities. Microblogs contain recent and popular software news. Software forges contain records of socio-technical interactions of developers. All these resources could potentially be leveraged to help developers in performing software evolution activities. In this chapter, we first present information that is available from these Web 2.0 resources. We then introduce empirical studies that investigate how developers contribute information to and use these resources. Next, we elaborate on recent technologies and tools that could mine pieces of information from these resources to aid developers in performing their software evolution activities. We especially present tools that support information search, information discovery, and project management activities by analyzing software forums, mailing lists, question-and-answer sites, microblogs, and software forges. We also briefly highlight open problems and potential future work in this new and promising research area of leveraging Web 2.0 to improve software evolution activities.