Nowadays you have the following execution models:
-Web Sites
-Cloud Services (Worker Role / Web Role)
-Mobile Services
-Virtual Machines
What are the differences between Cloud Services and Web Sites.
-Cloud Services:
You could integrate with Team Foundation Services and allow it to publish to Azure. (Continuous Delivery). With Cloud Services (Web Role), you have two environments in Azure, staging and production. You can use Staging to validate, and with one click (swap option), apply the new deployment package to production environment.
-Web Sites:
Web Sites is the right option when you want to create a simple web site. It is also a good choice for creating a low-administration web application, even one that must be quite scalable, or moving an existing IIS web app to the public cloud.
Cloud Services, which was the initial execution model provided by
Windows Azure, is an explicitly PaaS approach. While the line between
PaaS and web hosting is blurry, Cloud Services differs in some
important ways from Web Sites, including the following:
Unlike Web Sites, Cloud Services gives you administrative access to
your application’s VMs. This lets you install arbitrary software that
your application needs, something that’s not possible with Web Sites.
Because Cloud Services offers both web roles and worker roles, it’s a
better choice than Web Sites for multi-tier applications that need
separate VMs for their business logic. Cloud Services provides
separate staging and production environments, making application
updates somewhat smoother than Web Sites. Unlike Web Sites, you can
use networking technologies such as Windows Azure Virtual Network and
Windows Azure Connect to hook on-premises computers to Cloud Services
applications. Cloud Services lets you use Remote Desktop to connect
directly to an application’s VMs, something that’s not possible with
Web Sites.
http://www.windowsazure.com/en-us/manage/windows/fundamentals/compute/
More info:
http://www.windowsazure.com/en-us/manage/services/cloud-services/how-to-create-and-deploy-a-cloud-service/