Explanation:
The Simple Queue Service can be subscribed to the AWS Config topic (the Configuration Stream) which gives you a highly available and decoupled environment for the data within your Configuration Streams. By using SQS it allows you to create and use your own applications to extract only information and data that is pertinent to you. There can be vast amounts of data coming into the Configuration Stream, but you might only want to be notified and made away of any changes that may relate to any potential security issues. As a result, you may want to pull information from the queue that only relate to Security Groups/NACLs/IAM Roles or any other resource type that could affect the security of your environment.
Reference: http://docs.aws.amazon.com/config/latest/developerguide/monitor-resource-changes.html