With the deregulation of the markets and the introduction of new technologies, the need to manage diversification, change and complexity in product development has become crucial. To cope with this situation an alternative foundation for PLM is needed in which social issues are considered alongside with more traditional, technical ones. Such a major re-orientation of PLM needs to be informed by a theoretical perspective, which integrates social and technical issues into a coherent sociotechnical framework. To this end we propose the Activity Domain Theory. This theory has been used as a guide at the Ericsson telecommunication company in order to suggest an alternative foundation for PLM. Preliminary results are the enhancement of the organisational language with the construct of activity domains, a clean-up of fundamental categories in information management, a multi-domain product structure concept, an alternative business process model, an information system managing core information elements and a strategy towards balancing centralised and decentralised control.