This paper presents a model of entry into a network industry. The entrant tries to attract the customer base of the incumbent service provider. While the entrant is more efficient, the incumbent enjoys an advantage thanks to a bias in consumers’ expectations. Buyers enter the game with heterogenous beliefs as to which of the two firms is going to win competition. Then expectations converge - through higher order beliefs - and select one winner, who ends up being the single supplier. The path of expectations convergence crucially depends on the pricing policy followed by firms: so equilibrium beliefs are endogenous. Depending on parameter values, one of two outcomes obtains: (i) the incumbent is able to exclude the entrant, by lowering his price below the monopoly level; (ii) the entrant is successful, by undercutting the incumbent price. Productive efficiency and consumers’ welfare are hurt by exclusion; the entry threat is beneficial to consumers anyway. Imposing compatibility among networks is welfare improving, as it removes the exclusionary potential enjoyed by the incumbent.