...in several ways.
First, the plunging costs of information make it possible to find, then connect, two passions together far more efficiently than in the past. Once connected, cheap transactions keep the connection flourishing.
Second, symmetrical messaging, text, video, audio, 3D spaces, archives, privacy controls, all enhance the once slim attractions of a virtual community experience, keeping the community longer.
Third, the ubiquity of e-money in the network means that every niche has the ability to initiate an indigenous economy. The knowledge that dog breeders used to swap among themselves can become lucrative to the community as a whole when plugged into the network economy.
Fourth, the border-collapsing nature of the network economy means embryonic communities can theoretically draw upon a larger pool of potential members: all 6 billion humans. The law of increasing returns can feed a small interest into a mid-sized interest. Whereas once there was a lone fanatic for every notion, now there is a devoted web site for every fanatic notion; soon there can be 10,000 fellow enthusiasts for every fascination.