In this chapter, we discuss collaboration scenarios where people define services based on their dynamically changing skills and expertise by using Human-Provided Services. This approach is motivated by the need to support novel service-oriented applications in emerging crowdsourcing environments. In such open and dynamic environments, user participation is often driven by intrinsic incentives and actors properties such as reputation. We present a framework enabling users to define personal services to cope with complex interactions. We focus on the discovery and provisioning of human expertise in service-oriented environments.