Crowdfunding represents an alternative way of funding compared to traditional borrowing. As a principle, crowdfunding is open to everyone - private persons as well as economic actors. A group of people, the crowd, financially contributes small amounts to projects, products or ideas. These projects, products or ideas are owned by fundraisers (e.g. entrepreneurs or private persons), seeking for money in order to get their project realized. Fundraisers search for investors directly or via a specific digital platform, referred to as intermediaries. Crowdfunding represents a recent web 2.0 based phenomenon gaining more and more scientific attention. Therefore, this article seeks to give an overview on the current state of scientific knowledge on the topic, summarizing core definitions as well as characteristics.