Open source software communities work in a loosely knit organizational structure that works primarily on the motivations of gift and contribution of source code. They communicate using modern Internet-based applications and organize themselves into self-guided virtual communities. Several methods of collaboration and development of intellectual property through software within these communities are quite unique and innovative. Current research effort mainly focused on understanding the individual motivations, collaboration mechanisms, and associated project management challenges of various OSS projects. However, as open source software usage moves mainstream and becomes more and more widespread, factors drive its diffusion and adoption deserve more research attention. Using the concepts of innovation adoption, we attempt to examine the possible drivers that influence adoption of open source software within different open source communities. In particular, the results from two user groups - one from an OSS community in United States, one from an OSS community in India, are extensively compared and contrasted to gain better understanding of factors that lead to adoption and use of open source software.