In little more than a decade, the Web has become an essential medium for information, entertainment, and commerce, making its adoption among consumers quicker than any other medium before it. The majority of American classrooms have become connected to the Internet in the same short time span. Previously, science or mathematics students might have had access to only a few dozen images in a printed textbook; now, thanks to the Web, they have access to hundreds of thousands of images illustrating almost any conceivable topic. Likewise, teachers now face a new generation of robust web-based applications conducive to classroom use. With a wealth of resources categorized as "Web 2.0," search-weary teachers are increasingly challenged to mine the instructional gold within the fast-moving river of social networking tools. Coined by book publisher Tim O'Reilly, the term "Web 2.0" refers to a second generation of services available on the World Wide Web that allows groups of users to share information and collaborate online. In this article, the author considers two applications--(1) Del.icio.us; and (2) Flickr--in terms of their practicality and the unique ways they can enable today's teachers. The author describes the characteristics of Del.icio.us and Flickr and discusses how the two applications can be adapted for classroom instruction.