When users are asked the biggest problem they have with the World Wide Web, the number one response is getting the information they need. The wealth of information on the Web has raised the desire for tools to push and pull selected information to the desktop. Internet Explorer 4.0 improves upon the work in this area with Webcasting, which consists of two parts:

• Premium channels
• Subscriptions

Premium Channels

A formidable challenge for the Web today is providing a forum to deliver appealing content that takes advantage of the latest Web technology. Internet Explorer 4.0 gives content providers an opportunity to truly innovate, turning a portion of their Web site into a channel that resides directly on users’ desktops. Microsoft is working very closely with leading content providers to advance the viewer experience via premium channels for Beta 2.

Key Features of Premium Channels

• Premium content. Users will be a click away from the top content providers in the world.
  
  
• Active platform support. Inside the channels, you’ll see the most interesting, interactive content available, as these premium channels are specifically designed for Internet Explorer 4.0 with support for Dynamic HTML, ActiveX, and Java.
  
  
• Customization. Users can choose the content they’re most interested in, and it’s delivered directly to the desktop. Use the Channel bar to select your favorite topics, and Internet Explorer gets the information, so you can read it whenever you want–even offline.

What are the Benefits of Premium Channels?

• Exciting viewing experience. Before Internet Explorer 4.0, there was no reason for developers to spend time enabling their Web pages to take advantage of the newer, advanced technologies of the Internet. It was typical to develop for the lowest common denominator. However, with the Internet Explorer channel selector directly on the desktop, providers have a vested interest in making sure that their content is both informative and engaging.
  
  
• Personalized content. In the sea of today’s information, premium channels provide users with the best content available anywhere, yet users have the flexibility to customize their view. This way, they only get the content they need, like a customized multimedia newspaper. Users spend less time surfing the Web aimlessly, and more time getting the information they need.
  
  
• Efficiency. With the current limitations of HTML, it was difficult and time consuming to create truly engaging content that users could download and view quickly. With Dynamic HTML opening the door to more interactive Web sites and multimedia extensions, content providers can create fantastic sites that don’t require users to make time-consuming trips to the Web server.

How do Premium Channels Work?

On the desktop, an Internet Explorer 4.0 user has a channel bar that contains a set of buttons. Each button is stored as an Internet shortcut file on the user's hard disk, in the Channels folder. When the user clicks a button, Internet Explorer 4.0 opens (if it isn't already open), with the channel page specified by the shortcut. The channel page can support anything an Internet Explorer 4.0 HTML page can support, such as Java, ActiveX, or Dynamic HTML.

Every channel is a subscribed site, so the pages displayed are the ones most recently cached on the user's hard disk. Performance is fast, because the page is displayed from the hard disk. The creator of a channel provides a list of URLs—a Web collection file —that describes what content (HTML, images, class, and so on) is to be downloaded to the user's hard disk, as well as the schedule for downloading it, if they want to control the download schedule. If they don’t include those parameters, users can control when Internet Explorer downloads the content.

In the Web collection, the content provider can specify pages that are to be displayed in the default screensaver or perhaps a desktop ticker. Again, these are ordinary HTML pages displayed in a window more specialized than an ordinary browser.

An important note about both channels and the Active Desktop is that the desktop components must still provide information when a user is on the road, or at home, and they don’t have a permanent connection to the Internet. Therefore, the Active Desktop is enabled to work offline. Since most dial-up users do not have a constant connection to the Internet, a desktop component should display some reasonable content in the absence of a connection. This is of key importance, since the desktop is visible as soon as the user starts the operating system, even before they initiate a dial-up.

For this reason, any data files that the component requires should be cached on the local machine. Fortunately, the Internet Explorer 4.0 subscription feature, described below, can be easily configured to cache any object referenced by a desktop component. In the typical case where a component is built from an HTML document inside a floating frame, Internet Explorer 4.0 subscriptions can be set to automatically download any in-line images, objects, or applets, and download any number of HTML links N levels deep. The component can also specify individual subscriptions for any data files or objects it may reference.