This paper uses the WWW software market to empirically test the network externalities hypothesis in a market of composite goods. Among the results is that vendors that provide both components to a composite goods market (e.g. client and server) enjoy a higher price premium than do single product (e.g. server) providers.
Gallaugher, John and Wang, Yu-Ming, "Network Externalities and Composite IT Goods: An Empirical Investigation of the WWW Software Market" (1998). AMCIS 1998 Proceedings. 102.