The Pingback system is a way for a blog to be automatically notified when other blogs link to it. It is entirely transparent to the blogger doing the linking, requiring no user intervention to work, and operates on principles of automatic discovery of everything that it needs to know. A sample blog post involving Pingback might go like this: 1. Alice posts to her blog. The post she's made includes a link to a post on Bob's blog. 2. Alice's blogging system contacts Bob's blogging system and says, "look, Alice made a post which linked to one of your posts!" 3. Bob's blogging system then, when people view the posts on Bob's blog, notes on the page that Alice linked to this post. 4. Users can then follow this link back to Alice's post and read more.