The Amazon S3 Service Level Agreement came into being on October 1st 2007.
Just like any other company that provides network storage, Amazon Web Services has now provided a Service Level Agreement for its paying customers.
Amazon Web Services will use commercially reasonable efforts to make Amazon S3 available with a Monthly Uptime Percentage (defined below) of at least 99.9% during any monthly billing cycle.
In the event Amazon S3 does not meet the Service Commitment to its customers they will be eligible to receive a Service Credit.