When you want to add users without email address required in their profile in your Liferay instalation (from version 6 and later)
you can put the following properties in portal-ext.properties file
users.email.address.required=false
users.email.address.auto.suffix=@no-emailaddress.com
users.email.address.generator=com.liferay.portal.security.auth.DefaultEmailAddressGenerator