Changes in Web infrastructure have allowed ITexts to become a vehicle for transdisciplinary Web-scale collaboration so that large-scale teams can create new knowledge despite differences in team members’ disciplinary training, geographic location, and levels of expertise. In this article, the authors define Web-scale collaboration and illustrate the need for transdisciplinary approaches to problem solving. Then they introduce heuristics for creating and evaluating such transdisciplinary, collaborative Web-scale ITexts, drawing on examples generated at a workshop sponsored by the National Science Foundation that was held at Rensselaer Polytechnic Institute in April 2010.