Because it's not that easy: Who do I charge? The one person who signs up is able to create accounts in a private environment, e.g. for his fellow students, so this one is most likely the one to charge. This person would most likely be the class representative student. But I don't think this one is willing to pay money for all his fellow students using DocMan in his private environment, so.. that's the circle. The software was initially build for being used by a whole university, but as those in Germany are mostly broke or not willing to pay money for anything or both, I also cannot charge these. You see?