|  A Pingback is also a signal (ping) sent from Site A to Site B. However, it's also a link. When Site B receives the notification signal, it automatically goes back to Site A checking for the existance of a live incoming link, if it exists, the Pingback is recorded successfully. This makes Pingbacks less prone to SPAM than Trackbacks.
Both sites must be Pingback enabled in order to establish this communication. If a site is Pingback enabled, each time you link-out you will be "pinging" external sites. Pingback requires for Site A to phisically link to Site B. Pingback our Forums from another Site A Pingback will be registered in our forums by simply linking back to a thread or post from a Pingback enabled website. Note: If the forum administrator requires moderation for Incoming Pingbacks, a link-back to the site originating the Pingback will be published only after the Pingback has been manually approved by a moderator. Once a Pingback has been published, an automated notification email will be sent to the thread contributors. Pingback other Sites from our Forums Pingback other sites from our forums by simply including an outgoing link to a Pingback enabled site within your post. Note: If the Pingback recipient site requires moderation for Pingbacks, a link-back to the thread originating the Pingback will be published only after the Pingback has been manually approved by the recipient's site administrator. | 
"LinkBacks" is the generalized term we use to reference three methods of communication between Websites:
A Trackback is simply an acknowledgment. This acknowledgment is sent via a network signal (ping) from Site A (originator) to Site B (receptor). The receptor often publishes a link back to the originator indicating its worthiness.
A Refback is also a link. However in this case, Site A (link originator) does not need to "tell" anything to Site B (receptor). Instead, the receptor Site "discovers" this link immediately after the first web visitor gets to the site by clicking on the link. This is done by analyzing information carried by this web visitor's browser referer header.