Simplygon Cloud is an optimization service that runs on Microsoft Azure.
Simplygon is not a public service hosted on the Internet; it is a service acquired in the Azure Marketplace. This means that when you acquire a Simplygon instance in the Azure Portal, that Simplygon instance will only be used by you and whoever you provide access to.
If you need an on-premise solution, Simplygon is also available on Azure Stack, the on-prem version of Azure.
Azure Blob Storage
When Simplygon Cloud does processing, all input and output files involved in the process must reside on Azure Blob Storage. This is for efficiency reasons, uploading/downloading assets for every processing from/to a remote server or machine would potentially take a lot of time. Since many asset pipelines process assets in multiple successive steps it would become inefficient if every step required a transfer of assets. The transfer speed between the Blob Storage and the Simplygon instance is faster than from or to remote servers.