For yii users maybe ever had error when sending the emails in the localhost with some kinds of warning.
The error maybe like this :
mail() [function.mail]: Failed to connect to mailserver at "localhost" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set()
It has caused because in the localhost there is no mail server so you can even send email. To solve this issue you must install mail server in your local computer such as hMailServer.
Or if you want to use the mail server from your provider you can use the SMTP configuration email from the provider.