Eclipse/Orion uses OpenAjax Hub within plugin system
An exciting new open source project is the Eclipse Orion project. The Eclipse Orion project [1] (developer tools for the Web, on the Web) was announced in Jan 2011 and held planning meeting in March [2], where the Orion team showed the secure and extensible Web plugin technology approach that they are using, using OpenAjax Hub under the hood. Each “JavaScript plugin” gets isolated into its own iframe sandbox, and all communications across plugins are done with pub/sub messaging.
[1] http://www.eclipse.org/orion/
[2] http://wiki.eclipse.org/Orion/Planning_Meeting