Easier Platform To Manage:
Windows Server 2008, with Internet Information Services 7.0 (IIS 7.0), provides a security-enhanced, easy-to-manage platform for developing and reliably hosting Web applications and services. More than just a Web server, IIS 7.0 is a major enhancement to the Windows Web platform and plays a central role in unifying Microsoft Web platform technologies—ASP.NET, Windows Communication Foundation Web services, and Windows SharePoint Services.
The Windows Server 2008 Web and Applications platform helps to enable more efficient deployment and management, greater performance, higher security, and more customizable Web applications and services.
Use Only The Features YOU Want:
The componentized architecture is a critical property of IIS 7.0, leading to reduced security risks and minimized patching requirements. It also enables specialized server deployments, which combine select IIS features and custom components optimized for a specific server role in your application topology, such as reverse proxies and cache servers, HTTP protocol load balancers, or SSL and security sentinel servers.
Take Your Back-End Public. Easier.
All of the server features that ship with IIS 7.0 are built on top of new public extensibility APIs. As a developer, you have the ability to replace any of the existing server features with your own or build a new module to add to the IIS 7.0 feature set. Want to replace the built-in authentication mechanisms with a custom authentication module or provide a new form of response compression? Go ahead.

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Less time spent on features, More time spent on business.
The new extensibility APIs are a fundamental improvement over the previous ISAPI extensibility model, enabling you to enhance the server with much more flexibility and ease. Virtually every single aspect of the server, starting with the core server and continuing to configuration, management, and diagnostics, provides extensibility to allow you to extend and tailor the server to your own needs. More about extensibility later in the article
IIS 7.0 offers new capabilities that dramatically improve the way Web solutions are developed, deployed, and managed. Enhancements available in IIS 7.0 include: