Communities of Practice (CoPs) are seen as a primary vehicle for knowledge sharing across large and disparate organizations. It is therefore expected that technology will play a critical role in enabling global CoPs. The usefulness of information technologies (IT) to support CoP activity in two large, but quite different, global organizations is analysed and common themes developed. BHP Billiton is one of the world's largest diversified resources company, with a strong industrial heritage and a mix of blue and white collar workers and levels of IT literacy. CSC is one the world's leading IT service providers, with a highly IT literate staff and a relatively sophisticated IT support environment. Both organizations could be considered early adopters of the CoP concept. This chapter tracks their evolution and the lessons learned along the way.