• Both are free and open source web applications written in PHP which use a database such as MySQL.
• Both can run on standard, inexpensive hosting.
• Both use jQuery
• Both share the title of FLOSS Web Applications with the fastest release cycles

• How CMS architecture affects dev communities - A case study of WordPress, Drupal, Tiki Wiki and XOOPS
• Tiki offers a choice of rapid release or Long Term Support (LTS). With WordPress, you need to always stay in a rapid release cycle even when your site has all the features you need because WordPress doesn't offer an LTS version and this is unlikely to change because the project leader is "philosophically opposed" to Long Term Support (LTS) versions.
• Tiki is more centralized. Tiki is the all-in-one model while WordPress (like Joomla! and Drupal) is the small-core-and-add-what-you-need model. Each model has its pros & cons. Because of these design choices, Tiki is the CMS with the most built-in features. With WordPress, you can add tons of features via plugins. Please see: http://pluginproblems.com/
  • Tiki has all the features built-in (and you just activate/deactivate features), thus, every Tiki instance of a given version has the same code base. This makes it easier for a hosting company and for upgrades. In contrast, if you maintain dozens of WordPress sites, they will have different modules installed depending the use case.
  • When Tiki is upgraded, all the features are supported and the upgrade is smooth. In WordPress, some of your plugins/extensions may have become abandoned or be incompatible with the new version.
  • In Tiki, forums and social networking are done with built-in (optional) features, whereas in WordPress, they are separate projects
• While Tiki is a very large and popular project (over 300 contributors to main code base and over 1 000 000 downloads), WordPress has a much larger install base.
• Tiki is Wiki-centric, whilst WordPress is blog-centric. Please see (if) Why Wiki Syntax Is Important to your project.
• The Tiki community has a Dogfood philosophy while MediaWiki is used for the WordPress wiki.
• WordPress 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.
• Differences in themeing
  • WordPress themes are made with PHP/HTML. Some people prefer this, but it has risks such as this.
  • Tiki uses the Smarty template engine (which has many benefits), and by default, Smarty security settings prevent the use of PHP in Tiki templates, but you can override this if you need.
  • Because of use of PHP in templates, WordPress themes actually come with added functionality. Thus, if you change themes, you can lose some functionality. In Tiki, switching themes never makes you lose functionality and only affects the presentation (colors, layout).
  • Why WordPress Themes are Derivative of WordPress
• There is a WordPress to Tiki importer.

Compare them at http://cmsmatrix.org

https://www.openhub.net/p/_compare?project_0=Tiki+Wiki+CMS+Groupware&project_1=WordPress

Contributors (All Time) click "View as graph"
Commits (All Time) click "View as graph"

WordPress has a very large number of non-core developers and the stats for them do not appear here.

• Interesting Features from other Web apps
• A blog post in Spanish comparing Drupal and Tiki, and some comparisons to WordPress

• WordPress
• TikiWiki vs WordPress