Internet Explorer 8 (IE8) shipped with a new feature for web users called Web Slices. You can learn more about web slices here.
Essentially it lets you add enhanced links to your favorite bar that allow you to preview snippets of content from websites that you frequently visit without having to open up the page.
A web slice is content on a web page which a user can subscribe to. The content is then available from a button in the Internet Explorer 8 Favorite's toolbar. When the content is updated, the button glows orange to alert the user that there is new content. When the user clicks the button, they see a drop down window with the updated content of the web slice.
To enable Web Slices on your PHP web site. We have created a project, Web Slices and Accelerators for PHP that lets you get started quickly and the source is available on Codeplex too. The solution contains HTML and PHP samples to create web slices in WordPress, Wikimedia and Facebook,, all popular php blogging, content and social sites that you may want to have your code interoperate with to get started. Download the package and unzip the file to a directory on your machine.
Check-out the detailed blog post at: http://blogs.msdn.com/interoperability/archive/2009/11/20/php-and-ie8-web-slices.aspx