Summary Peer-to-peer (P2P) computing is currently receiving a great deal of attention. Much of the current attention is focused on the use of P2P computing for exchanging media files. But P2P systems have actually been around for a long time and many application scenarios exist. In this paper we discuss on one hand the evolution of P2P middleware from simple file-sharing to decentralized data storage; on the other hand the impact on the future development of decentralized workflows. Building up a P2P based data storage, with similar properties as a standard data store, opens many research issues. While P2P databases enable distributed data storage, distributed control flows are considered in decentralized workflows. The paper will present several research issues addressing the collaboration and coordination problem in distributed environments without a centralized coordination instance by means of a B2B application scenario.