A trackback is a feature of a blog where readers can “trackback” to past posts. When a reader clicks on a link in a post that leads to another post on the blog, the blog software creates a trackback URL, which includes the post ID and the date/time of the click.
The trackback URL appears as follows:
When a reader clicks on the trackback URL, the blog software takes them to the previous post, with the comment text still visible. The reader can then continue reading or commenting on that post as if it were their own.