Re: Personal wiki for a user
admin -> wiki -> Page creators are admin of their pages:
and take away the tiki_p_edit, ... perms in the registered group (admin->groups->the group key)
Nevertheless there is a bug in 1.9.2, you need to apply a patch to have this working
http://cvs.sourceforge.net/viewcvs.py/tikiwiki/tiki/tiki-editpage.php?r1=1.89.2.50&r2=1.89.2.51