The aim of this work is to describe the interdisplinary research relationships among several Spanish university departments and research groups located in the Spanish web space. 699 web sites from 2390 were selected according to whether a web site receives or links to at least one of the rest. The links between them were extracted with a commercial crawler in 2004 and then analysed to built a complex directed network of in-links and out-links. The results show that the Spanish academic web space is weakly interconnected both at the level of groups and departments, and that the relationships between disciplines can be appreciated through network graphs. The use of network graphs is a suitable technique to show the transversal relationships among disciplines and to detect incipient research fronts in the web space. The web presence of Experimental and Technological Sciences is higher than Social Sciences and Humanities as well.