Volunteered Geographic Information (VGI) is a recent trend that has been successfully used in order to collect and share geographic information. This method is of interest for scientists who are in need of data and who want to get people involved in their cause. In this paper we discuss the challenges and opportunities that scientists may face when using the concept. An initial challenge is to find users who are willing to contribute. Second scientist must get these users to interact with the application and with each other. The final goal is to end up with high quality data that can be used for scientific research.