The aim of information logistics is to reduce information overflow by utilizing the paradigm of a demand-oriented information supply. In this paper we focus on asynchronous message-based communication processes in collaborative environments. Our main task in this context is the assessment of messages with respect to the situations of the receiver. This paper presents a new general approach to estimate the information value of free text messages (e-mail, fax, etc.). Our measure for information value is based upon relevance between a message and different situations as well as time- and situation-dependent utility and acceptance functions. The approach has been tested using the MeLog system implemented at Fraunhofer ISST. We use a scenario from the automotive industry to demonstrate its general applicability. Finally, we focus on the application potentials of our approach in cooperative environments where the efficiency of information and communication processes is of crucial importance.