Mäkitalo, K. and Häkkinen, P. (2001). Building and maintaining common ground in web-based interaction. In Proceedings of the 9th Conference for Research on Learning and Instruction, Friburg, Switzerland. Available from: http://newmedia.colorado.edu/cscl/123.pdf.
Interesting link provided by this paper points to Veerman (2000). This author expand on Dillenbourg and Traum 1999 and says that grounding can exist also at the level of understanding thematic information in relation to certain task and learning goals.
The authors here state that this is achieved through negotiation, which they consider central to collaborative learning. For them collaborative learning environment should be designed to offer possibilities of disagreement and misunderstanding as well.
For them the key of people interacting in such environments is for them to keep the focus not just on the content but also in the way they are proposing such content. They have to be mor eaware of the reactions of the partners to their contributions. They have to seek evidences. The central claim is that even when adaquate level of common ground is established, it does not guarantee that interaction will continue. They say that this common ground has to be maintained by heeding mechanism of contact, perception, understanding and attitudinal reaction.
They are extracting this four levels from a study by Allwood (1991). However, I have got the impression that they mixed up these four levels with the concept of linguistic feedback, which they represent into a separate filed in the diagram of the mechanism of common ground. On the contrary, for Allwood, this feedback is embedded in the four levels described.