It is commonly argued that when innovation is sequential, and the product has network externalities, incumbents build a large network that inefficiently blocks the entry of future incompatible innovators. This paper shows that when intellectual property rights permit some degree of compatibility...

Social contacts help workers to find jobs, but those jobs need not be in the occupations where workers are most productive. Hence social contacts can generate mismatch between a worker's occupational choice and his comparative productive advantage. Thus economies with dense social networks can...