Magento go is advnce version of software as a service(SaaS) it is a platform as a service (Paas)

Magento is a combined structure of  Community professional and enterprise edition .In magento go

 a well structured centralized database is there to provide you business logic of  your magento store. It
is more over a advance hosting service for your magento web store.There are similar webs shop like magento go are BigCommerce and shopify.