Mailer Plugin is an add-on for WordPress which transparently capture emails sent by WordPress (or plugins) and deliver it slowly (technically throttles them). This plugin is perfect for everyone uses a shared hosting where the provider imposes limits on the number of emails per hour.
Other than it’s main function of throttling emails, it lists those features:
- SMTP enabled: you can configure an external SMTP to be used to send emails
- delivering priority: plugins can send email setting a priority; that avoid real time email (like password recovery email) to be blocked by a long queue (for example from a mass mail to all users)
- return path setting to get the “delivery errors” sent to a specific mail box (most provider catch the delivery error messages and put them on the server user account mail folder which most of the time is not available)
On Mailer official page there is a link to download it from WordPress or you can search it from your blog plugin panel.