The negotiation of what is to count as mutually acceptable collaborative knowledge is difficult to conduct when participants cannot interact face-to-face. We review certain related work on negotiation support and develop a concept of “knowledge negotiation” that is appropriate for collaborative learning in ALNs used in school classrooms. This concept is situated within the framework of collaborative knowledge building viewed at the group unit of analysis; it contrasts with negotiation as the reconciliation of multiple personal opinions through voting. We then describe an implementation of support for knowledge negotiation in an ALN that is currently being tested in European schools.