What’s a Pingback, you ask?
When you link to another WordPress site, a pingback is made – if that WordPress has enabled pingbacks. You could call it a remote comment.
I personally like pingbacks, it’s good to see who’s linking to my posts.
Person A posts something on his blog.
Person B posts on her own blog, linking to Person A’s post. This automatically sends a pingback to Person A when both have pingback enabled blogs.
Person A’s blog receives the pingback, then automatically goes to Person B’s post to confirm that the pingback did, in fact, originate there.
To create a pingback, just link to another blog post. If that post has pingbacks enabled, the blog owner will see a pingback appear in their comments section that they can approve.
If pingbacks annoy you, you can turn them off on individual posts
or turn them off existing posts using the Quick Edit function, explained here Turn off Comments and Pingbacks on Existing Posts