Visualforce

Visualforce gives customers the power to design application user interfaces for any experience on any screen. Using the powerful logic and workflow intelligence provided by the Apex programming language, Visualforce offers the flexibility to meet the requirements of applications designed for many different types of users on a variety of devices. Now you can create and deliver any user experience you can dream up.
Visualforce provides a page-based model, built on standard HTML and Web presentation technologies, and is complimented with a component library for implementing common user interface elements, and a controller model for creating new interactions between those elements. As part of the larger Force.com platform, the user experiences created in Visualforce directly leverage the data, logic, and workflow created in the other Force.com features. Visualforce features and capabilities will include:
Pages – This capability enables the design definition of an application’s user interface. Implemented using standard Web technologies including HTML, AJAX, and Flex, pages will dynamically detect devices and associate them with specific design definitions. Pages will allow customers to create any user experience with standard Web technologies that will be immediately familiar to any Web developer and give them the ability to automatically deliver the right experience to the right device.
Components – With components, you can create new applications that automatically match the look and feel of Salesforce applications or easily customize and extend the Salesforce user interface to specific customer and user requirements. Customers can rapidly create a user experience by assembling existing user interface elements. Visualforce will provide the power to reuse predefined standard Salesforce and custom-designed UI components. More than 50 standard Salesforce UI elements will be available with Visualforce.
Logic Controllers - The controller enables customers to build any user interface behavior. Customers will be able to use Visualforce to quickly create a new look and feel that leverages existing application functionality. Customers can define completely new UI interactions that benefit from all the power of the Apex programming language. The standard controller gives customers the ability to inherit and reuse any standard Salesforce UI behavior, like new, edit, and save. Customers will also have powerful custom controller capabilities to define new UI behaviors using Apex.