This article shows how engagement with the internet and aspects of the new economy/society require an appreciation of union difference and politics. It shows how union responses vary due to four factors: communication strategies, union identity, forms of internal democracy and a range of organisational and social contingencies. The article will study the phenomena of the internet in the context of one national case study, Spain. It is a country that allows us to view the political dimensions of the internet, and the way they link to communication strategies, due to the manner in which the labour movement has transformed and modernised itself. It is also of interest because methods of communication have been at the heart of the way in which unions have developed and differentiated themselves. This article will argue that a greater sensitivity is required in terms of union history, politics and identity if the impact and use of new forms of communication are to be fully appreciated. It also points to the need to appreciate tensions between different forms of communication.