For many years, it was tikiwiki.org

More recently and part of the new branding strategy, it is tiki.org


tikiwiki.org still works and permanent redirects will

gateway pages

This is quite useful to have gateway pages such as tiki.org/model or tiki.org/download

Questions

What should be presentation?

Alone

tiki.org
Tiki.org
Tiki.Org
TIKI.ORG

Surely not:
www.tiki.org (www are old skool and of not use)
www.Tiki.org (www are old skool and of not use)

With gateway pages

tiki.org/model
tiki.org/download
tiki.org/Model
tiki.org/Download
Tiki.org/Model
Tiki.org/Download