Back from the ICWE 2006 conference, finally I found some minutes to re-think about all the talks seen there and papers read in the proceedings. Actually, I found out that there are many approaches to model systems. Finally, there are a few questions I think about when I hear the term model:

1. How easy is it to create and change the model? Do I need tool support or can I do it using pen and paper?
2. Is the model machine-readable? Can I process the model in any way? What is the benefit of the model?
3. Do I create the model and the the artifacts depicted in the model or do I create the model with respect to the artifacts i have found? What happens if these artifacts change?
4. In school I learned in chemistry about models. For this our teacher showed us a Matchbox car.