An oft-noted shortcoming of the research on teaching has been the meager description of teachers' knowledge and experience: their intellectual engagement with the subject matter they teach, their understanding of how to manage ideas in their teaching, or even their conceptions of how students develop knowledge of the subject matter taught. To address this need, the Knowledge Media Laboratory (KML) of the Carnegie Foundation has explored how Web technologies can support focused inquiry into the link between pedagogy and practice. Developed to help teachers create compact and engaging representations of their teaching knowledge, experiences, ideas, and reflections, the KEEP Toolkit is a Web-based tool suite that was released as open source software in 2006. Iiyoshi, Richardson, and McGrath first describe the key features of the KEEP Toolkit, discuss its early use by Carnegie scholars, and illustrate its use by contributors to the MERLOT learning object repository. They then outline the motivation and planning behind the transformation of the KEEP Toolkit from a specialized in-house tool to an open-source software application to foster educational knowledge sharing for a worldwide network of users.