Tim O'Reilly
The phrase Architecture of Participation comes from web publisher, entrepreneur Tim O'Reilly[1] who used it to describe the nature of systems that are designed for user contribution, such as open source software, wiki and other collaborative authoring tools.
The phrase has come to define one of the key elements of what's been called Web 2.0, which describes the collection of companies, technologies and projects that are designed around the culture and economics of open athorship and distribution.