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

• Plone is GPL, Tiki 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 written in Python, while Tiki is in PHP.
• Plone started in 1999, and Tiki in 2002

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

Compare them at http://cmsmatrix.org

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

Number of commits made to the project source code each month.

http://www.realstorygroup.com/Blog/248-Does-a-sticky-Wiki-make-a-CMS?

• Plone
• TikiWiki vs Plone
• Tiki vs Zope Not really comparable but Zone & Plone are closely associated