Plone is a
free and
open source content management system built on top of the
Zope application server. Plone is positioned as an "Enterprise CMS" and is most commonly used for
intranets and as part of the web presence of large organizations. High-profile public sector users include the U.S. Federal Bureau of Investigation, Brazilian Government, United Nations, City of Bern (Switzerland), New South Wales Government (Australia), and European Environment Agency. Plone's proponents cite its security track record and its accessibility as reasons to choose Plone.