Wagn grew out of Grass Commons' efforts to build a consumer education site capable of organizing to the rich and variegated data we all need when trying to make wise, ethical decisions about how to use our money.

Ethan McCutchen and Lewis Hoffman first conceived of Wagn at RecentChangesCamp, an Open Space conference on wiki and community that was first held in Portland, Oregon in February, 2006.  They opened up the source code for Wagn in April and then launched Wagn.org in July. John Abbe was in some conversations that inspired Wagn's core ideas, then joined the team in January, 2007.

In August of 2006, Grass Commons was awarded a development grant from Meyer Memorial Trust, Oregon's largest private foundation and an avid supporter of open source projects of social import. Since then MMT has funded two further rounds of major development. With this support, Grass Commons was able to release a strong version 1.0 in June, 2009.

Wagn was named a finalist for the Tides Foundations' Pizzigati Prize for public interest computing and nominated for the Mellon Awards for Technology Collaboration.