The jump was partly from RackSpace to Azure Cloud. In the process the entire on-premise infrastructure has also been moved to Azure according to
JumpStart is a leader in the learning-based multiplayer games for kids with recent releases like School of Dragons and Madagascar Math Ops.
According to a JumpStart article it has thrown all of its eggs in Azure basket that includes all of its web content, web and mobile game products to Azure.
Read more about this here: http://www.jumpstart.com/aboutus/press-releases/jumpstart-transitions-to-microsoft-azure-scalable-cloud-technology