I'm still coming to understand the full power of blogs. Scott Watermasysk explains how tracebacks work in .Text (the software used to run this blog). As an example, this post will attempt to ping Scott's main site, and his post. Scott's site will download this post and verify that there's really a link to his site on it (to prevent spam). It will then add a comment to his post with a reference to my post. He'll also be able to see that I linked to him. This is very cool - it's a simple way to share information and generate mutual links to information.