Amazon has announced a new secret region - I'm not sure why they're calling it a Secret Region given they 've announced it - for workloads up to Secret U.S. security classification level. If you've need to run workloads that require higher security than AWS' regular services then this is for you.
AWS says this makes them the first and only commercial cloud provider to offer regions to serve government workloads across the full range of data classifications, including Unclassified, Sensitive, Secret, and Top Secret.
With one of the arguments sometimes made against cloud services being concerns about security, it makes sense of AWS to try and differentiate themselves from their competition. I'm guessing we'll see a similar announcement from Microsoft and the Azure team soon as they won't want to be seen as lagging.
Security continues to be a key differentiator between different cloud platforms with service providers in an arms race to stay ahead of attackers. This move by AWS, while only really being about meeting the needs of a small sub-section of their customers, will boost their credilbility. I'd also expect some of the more hardened features to eventually make their way into AWS' mainstream products.