Amazon Simple Email Service, or SES, provides cloud-based email as a service. Amazon SES simplifies sending emails from applications being hosted on services such as Amazon EC2. Because email services are often used by spammers, Amazon SES provides each user with a quota. EC2 users can send 2,000 emails per day for free.
The service allows developers to send either raw email or formatted email using Amazon's SMTP servers. Any spam complaints or other issues bubble back up to the developer. Similar to other Amazon Web Services, Amazon SES charges per gigabyte for transfer in and out of its systems.