Discourse, a form of collaborative learning, is one of the most widely used methods of teaching and learning in the online environment. Particularly in large courses, discourse needs to be "structured" to be effective. This in-progress study investigates how to "scaffold" asynchronous discourse based on the Asynchronous Learning Networks Cognitive Discourse Model (ALNCDM). The ALNCDM is an adaptation of Clark and Brennan's grounding in communications principles within a technology- mediated learning (TML) environment. The model applies content and process scaffolding based on pedagogic principles. The study is a 2 X 2 design measuring learning effectiveness. Results of a pilot study are described. A major contribution of the study is building and testing a technology-mediated, discourse- centered, teaching and learning model called the ALNCDM.