Many think that USV is a consumer web investor. We don't think of ourselves that way. We invest in networks and for most of our short history, that has meant investing in networks of individuals connecting with each other. Thus the consumer web investor moniker.
I like to think that our first foray into this kind of network was 10gen, the company behind MongoDB. MongoDB is an open source datastore for web scale applications. The first users were developers who wanted a simple, easy to get started datastore. It was perfect for hackathons and such where the developer needed to get something up quickly. This post I read yesterday does a good job of explaining why MongoDB took off. These developers became a network of users and contributors to the open source project. Many of them worked in enterprises and brought MongoDB into their teams. Soon enough 10gen started getting calls from executives saying something like "I just learned that we have 50 instances of MongoDB in production and I'm eager to get a support contract". That's where the enterprises joined the network.