Accounting is an essential part of distributed computing infrastructures, regardless whether these are more service-driven like Clouds or more computing oriented like traditional Grid Computing environments. Those infrastructures have evolved over more than the last decade and additional. beside the further development towards service-oriented architectures, the business aspect of especially Cloud Computing solutions becomes more and more relevant. In this paper we focus on user-centric aspects like privacy preserving methods to hide the users behaviour and to collect only necessary information for billing, under the assumption that an accounting system has to be integrated in the computing infrastructure and that a central interface is still desirable for billing and financial clearing.