An automated cross referencing system between blogs. When you make a comment on your blog about a subject posted on another blog, Pingback is used to enable that blog to link back to the comment on your blog. Unlike TrackBack, the link back does not include a title and excerpt; however, it is more automatic as a result.

Both blogs must use blogging software that supports the Pingback protocol. When the Pingback is initiated, your blog software automatically contacts all the sites you have linked in your blog to see if they accept Pingbacks. See TrackBack.