Steven Chau sent in an interesting article this morning - ones that talks about how one of the cooler addons for a search engine works - the Google Toolbar. It's surprisingly simple, really, and is based off of an XML format that allows the toolbar sitting in your browser window to get information back from the Google.com servers.

The author uses a Java applet to capture everything being sent back and forth between the servers and his clients, so you can clearly see where the toolbar gets the information from and how it's all formatted. He even gives you a sample XML page that shows you this structure.

This is one of the cooler uses of XML that I've seen so far, and even better that it's attached to Google!