• Both are written in PHP and use a database such as MySQL

• Concrete5 is MIT, Tiki is LGPL.
  • "Add-ons and Themes for concrete5 can be offered under any license. Most of the add-ons available in our marketplace are either completely free and licensed under MIT as well, or they are commercial add-ons and offered under our standard commercial license. These add-ons are sold on a "per-instance" basis. This means one add-on purchase per live site. Development copies and stages are included."
  • Tiki is the all-in-one model and thus, all features are Free and Open Source.

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.

• Concrete5
• TikiWiki vs Concrete5