Compare them at http://www.wikimatrix.org/compare/Tiki-Wiki-CMS-Groupware+SocialText

• Both are full-featured enterprise wiki applications.

  
  

• Tiki is Free/Open Source software whereas SocialText is SAAS or deployed as an appliance
  • If there are things you prefer in SocialText, you can take the money you save and invest it to improve Tiki 😀
• SocialText is in Perl and Tiki in PHP.
• SocialText used to have a Free/Open Source version, but no longer.
  • If there are things you prefer in SocialText that are not in the Free/Open Source version, you can take the money you save and invest it to improve Tiki 😀

    
    

• SocialText
• TikiWiki vs Socialtext