I need help. How unregistered start discussions.

Hi, Im New here. I need make unregistered user permissions to start new discussions for donated site for help chilean people find him family. Most of them arent usualy users of internet, so they havent e-mail account. The idea is that Disscussions will be names of peoples. You can see the site in http://www.congechilemendoza.com.ar/buscarpersonas
Im not write fine in english, sory. Im from Mendoza - Argentina. Thanks.