- Both are full-featured free and open source web applications with which you can realize a very diverse variety of projects.
- Both are written in PHP and use a database such as MySQL
- Both can run on standard, inexpensive hosting.
- Both have large & vibrant communities
- Both have a template layer
- Tiki is more centralized. Tiki is the all-in-one model - all modules are part of the package while Typo3 (like Joomla!) is the small-core-and-add-what-you-need model (you need to use third party modules out of the package). Each model has its pros & cons.
- Tiki is more focused on collaboration and structured wiki (customisable data management) over the web while Typo3 is more focused on web publishing.
- Tiki is relying on the Wisdom of Crowds to shape its development model (while some people see it as the infinite monkey theorem instead). Consequently Tiki can suffer from a diffusion of responsibility since everyone only works on what interests them and not necessarily ensuring up to date documentation and basic reliability in some cases. Typo3 follows a professional open-source business model whereby people who contribute to the project can get compensated for their work.
- Typo3 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.
Compare them at http://cmsmatrix.org