This article describes the importance of annotation to reading and writing practices and reviews new technologies that complicate the ways annotation can be used to support and enhance traditional reading, writing, and collaboration processes. Important directions for future research are discussed, with emphasis on studying how professionals read and annotate, how readers might use annotations that have been produced by others, and how the interface of an annotation program affects collaboration and communication on revision. In each area, the authors emphasize issues and methods that will be productive for enhancing theories of workplace and classroom communication as well as implications for the optimal design of annotation technologies.