In recent years, crowdsourcing technology has been heavily researched by academics and at the same already been applied to real-life projects by practitioners, promising to connect large agile crowds of workers for quickly solving even complex tasks with high-quality. Some impressive use cases show that crowdsourcing has indeed the power to shake up established workflows in companies, helping them to stay competitive and innovative. However, the rising popularity of crowdsourcing will also have a societal effect on the worker population by changing the rules imposed by traditional employment models. In this paper, we explore different types of crowdsourcing techniques and discuss their individual capabilities, but also their (current) limitations. In addition, we provide an overview of open research challenges not only for ICT research, but also for legal, social, and economic research.