In February 2018 Wikispaces.com announced that it would be shutting down. The scheduled closure of services is: "Classroom and Free Wikis end of service: 31st July 2018; Plus and Super Wikis end of service: 30th September 2018; Private Label Wikis end of service: 31st January 2019" Appropedia could serve as a new home for the content currently hosted on sustainability-related wikis on Wikispaces. Below is an list of some of the relevant wikis.
Admins can export their wikis' data by following these instructions.
Wikispaces has been particularly popular with educators. They may be interested in Appropedia's focus on service learning and other education resources.