Similar

• Both are collaborative application with lots of features.
• Both are very present in the enterprise

Different

• Sharepoint is a commercial product, while TikiWiki is a community-managed open source project. License: LGPL.
• TikiWiki is a LAMP application whereas SharePoint is is designed to run on a Windows Server.

References

Even references that don't directly discuss Tiki may have comparisons are relevant to Tiki.

How good is MS Sharepoint as a wiki? WikiSym.org

• Sharepoint vs Twiki. twiki.org.
• Comparing Sharepoint to Confluence?. Atlassian blog. 2009-03-06.
• MS Sharepoint as a Wiki: Few functions, less compatibility. Seibert Media blog. 2009-02-27.

Alias

• SharePoint