Microsoft talks up the new IE 8 Favorites Bar which, as it turns out, isn't so new:

The Favorites bar, previously known as the Links toolbar, has been updated with great new functionality that helps you get information from your favorite websites quickly and easily. The new IE8 Favorites bar still has your favorite links just one click away, but also allows you to add WebSlices (new feature debuting in IE8) and feeds to the Favorites bar, facilitating your navigation experience. The WebSlices and feeds on the Favorites bar will check for updates to content on your favorite websites without requiring navigation to those websites.

What is a WebSlice?

As Jane described earlier in her blog post , the new IE8 WebSlice feature enables you to see when updated content (such as auction prices or latest headlines) is available from your favorite websites.  A WebSlice is a piece of a webpage (a “slice”) that you can subscribe to. When you subscribe to a WebSlice, it appears as a shortcut on the Favorites bar.

Note that WebSlices will only appear on webpages that provide support for WebSlices. As of today, websites such as Ebay, Facebook and Stumble Upon have added support for WebSlices. Check out this page to learn how you can add support for WebSlices on your webpages.