BlogTalk, the International Conference on Social Software, brings together different groups of people using and advancing the Internet and its usage: technical and conceptual developers, researchers with interdisciplinary backgrounds, and practitioners alike. The focus is on social software as an expression of a culture that is based on the exchange of information, ideas and knowledge. The present volume includes 6 papers from BlogTalk 2008 as well as 11 papers from BlogTalk 2009. The areas discussed include: forms and consequences of emerging social software practices; social software in enterprise and educational environments; the political impact of social software; applications, prototypes, concepts and standards.