In 2003, the UK `liberalised' its telephone directory enquiries service with the aim of introducing competition so as to improve quality and lower costs. Unfortunately the results did not match expectations. Proliferation of numbers led to consumer confusion and high price firms with no...

A sizable literature has grown up in recent years focusing on two-sided markets in which economies of scale combined with complementarities between a platform and its associated ‘software’ or ‘services’ can generate indirect network effects (that is positive feedback between the number...

(In)direct network effects arise frequently in economic models but, for reasons of analytical tractability, are often assumed to be linear. Here, we examine the general non-linear case with two platforms. We establish the conditions characterising equilibria and show that welfare changes can be...