This study explores intranets as information infrastructure and this conceptualization is supported by evidence from three interpretive case studies. If an intranet is considered as an infrastructure then it does not occur ‘de-nouvo’, it must wrestle with an ‘installed-base’ and over time extends as a new infrastructure. If this is the case what are the social arrangements that are embedded and give visibility to the Information Infrastructure? What are these existing ‘installed bases’ that an Intranet wrestles with? A qualitative analysis strategy exploiting qualitative analysis software enhances this research. This study concludes that web-based information resources are in fact an information infrastructure, which do not occur ‘de-nouvo’. They ‘wrestle’ with and extend the existing non-technical organisational communication structures, taking on their strengths and weaknesses. They also ‘plug’ into other technical infrastructures in a seamless way. Business processes are also inscribed on to the information infrastructure, but in a partial manner rather than full-automation. A model of this nature can help the IS professional to more purposively extend an Intranet to a business critical information infrastructure.