This document discusses how ideas and memes spread through online communities. It defines memes as snippets of cultural information that are shared person-to-person until they enter widespread consciousness. Opinion leaders are identified as influential individuals who shape attitudes within a community. The concept of social capital is introduced as the resources accumulated through community relationships that can be traded for other benefits. LinkedIn and selectively accessed online communities called "gated communities" are provided as examples of networks that enable the building of social capital.