Hi Jason,
As most Linux programs, cp also needs an argument in order to copy
everything.
Ty it this way:
cp -r /home/domain1/www/* /home/domain2/www/
bith this will omit dotfiles. It will be much easier to:
cd /home/domain1/ ; cp -r www/ /home/domain2/
assuming, there isn't www/ in /home/domain2/
and don't forget to chown once the copy is over