This sets preferences for the domain in a cookie.
The server then tries to obey.
If date and time fields have been computed to text it will not work.
It might also mess up any date pickers you have.
May be it is not worth burdening your users with this information ;)
Try it here: http://notesninjas.com/$preferences.nsf
NB: To change the look and feel try looking at the files like: prfxxx.htm
NB: You can set the cookies yourself you do not have to use this interface...