We document that the Bay Area rose from 4% of all successful US patent applications in 1976 to 16% in 2008. This is partly driven by the increase in the prevalence of information and communication technology; however, even for patents unrelated to information and communication technology, we see a disproportionate increase in the share of US patents from the Bay Area. We interpret this growth as a trend to coagglomeration in invention across technologies, and explore different dimensions of this trend.

How did the diffusion of the internet affect regional wage inequality? We examine the relationship between business investment in advanced internet technology and local variation in US wage growth between 1995 and 2000. We identify a puzzle. The internet is widespread, but the economic payoffs are not. Advanced internet technology is only associated with substantial wage growth in the 6 percent of counties that were already highly wealthy, educated, and populated and had IT-intensive industry. Advanced internet and wage growth appear unrelated elsewhere. Overall, advanced internet explains over half the difference in wage growth between already well-off counties and all others. JEL: J31, L86, O33, R11, R23