For what it's worth, here's a def from UD

Interactive media theory where an infrastructure focusing on content creation, management, and dissemination is built for the user to generate that content in a community framework.

Urban Dictionary falls under the Web 2.0 theory because they built an infrastructure to create, manage, and disseminate the definition of slang terms generated by the user and ranked by the community--Jason D. Schwartz

dalehileman