Modern business strategies consider Web-based outsourcing of microjobs to the masses. Respective business activities are however difficult to manage. Traditional approaches of covering human tasks in business processes build on assumptions of limited process scale and closed organizational models that are not valid in crowdsourcing scenarios. Web services have been proposed as a means to represent human tasks that allow leveraging interaction, brokerage and composition capabilities of SOC for human interaction management. In this paper we argue that crowdsourcing requires considering qualitative constraints and sketch a platform for managing the quality of human-based eServices.