Foswiki is a fork of Twiki so the comparative information will mostly apply.
Wiki Matrix
Compare them at http://www.wikimatrix.org/compare/Tiki-Wiki-CMS-Groupware+FosWiki
Active contributors
Number of contributors who made changes to the project source code each month.
Tiki is in red
Activity
Number of commits made to the project source code each month.
Tiki is in red