The increased availability and quality of open source software on the Web is creating more opportunities for developers to reuse software and is changing the way developers write source code. It is important to understand how developers look for source code on the Web so that tools and approaches can be suggested to better support developers' needs. Based on different approaches to understand how humans look for information, we propose a five-stage model to differentiate the stages that could take place when developers look for source code on the Web. We use this model to assess the effectiveness of existing tools.