From CUNY Academic Commons
A sandbox is a testing environment that isolates untested source code changes and outright experimentation from the production environment or repository, in the context of software development including Web development and revision control.
Wikis also typically employ a shared sandbox model of testing, though it is intended principally for learning and outright experimentation with features rather than for testing of alterations to existing content (the wiki analog of source code). An edit preview mode is usually used instead to test specific changes made to the texts or layout of wikis pages. In the Academic Commons, a sandbox exists for users to experiment with their ideas and questions.
Sandboxes used in Electronic Literacy Programs
Project Stretch is a traditional and electronic literacy program. It utilizes wiki sandboxes within a MOODLE in order to encourage middle school students to experiment with online media.