Similar

• Both are full-featured free and open source web applications.
• Both are community-run projects
• Both have large & vibrant communities

Different

• Plone is GPL, TikiWiki is LGPL. The main difference between the GPL and the LGPL is that the latter can be linked to (in the case of a library, 'used by') a non-(L)GPLed program, which may be free software or proprietary software.
• Tiki can run on standard, inexpensive hosting while Plone needs more.
• Plone is witten in Python, while Tiki is in PHP.

Active contributors

Number of contributors who made changes to the project source code each month.

CMS Match

http://www.cmsmatch.com/compare/content-management-systems/844+1073

CMS Matrix

Compare them at http://cmsmatrix.org

Alias

• Plone