In using weblogs, you have likely seen the word TrackBack or TrackBack URL - this post will help you understand what TrackBack is, why it exists and how to use it, in Plain English.
TrackBack could be compared to carbon copying someone on an email. Suppose you write an email to your manager and talk specifically about a person on your project team. In this case, you'd like the person mentioned in the email to be aware that you mentioned them, so you add their email address to the CC: line of the email. This let's them know- I'm talking about you, and I want you to know.
In the weblog world, TrackBacks accomplish the same type of notification (also called a ping). It allows one weblogger to notify the other in an effort to say I"m talking about you, and I want you to know. Instead of a carbon copy on an email, the weblogger uses a special URL (called a TrackBack) that sends a notification to the specific weblog entry it would like to notify. When a TrackBack has been sent from one weblog to another, the receiving weblog displays the TrackBack like a comment:
How do I use TrackBacks, as a reader of weblogs?
TrackBacks allow you to navigate to other weblogs, where people are commenting on the subject-at-hand. By following the TrackBack links at the bottom of weblog entries, you are likely to find a variety of perspectives and opinions regarding a single weblog post. It lets you see how others in the weblog community are responding to the post. In this way, TrackBacks allow you to navigate a community of discussions across multiple weblogs.
How do I use TrackBacks, as a Weblogger?
First, understand that not all webloggers enable TrackBack functionality. When they do, you should see a TrackBack link at the bottom of an entry. Once you find the link, copy it, and go to your weblog tool and create a new entry related to that post. Before posting your entry, paste the TrackBack link into your weblog tool. In Movable Type, the field is called "URLs to Ping". Once you've pasted the link into the tool, it will send the notification to the other weblog once you post your entry.
What a pain! why isnâ€™t it easier?
Actually, there is an alternative called Auto Discovery and it has to be turned on in your Movable Type control panel (versions 2.5 and up). Using Auto Discovery, you don't have to futz with the TrackBack link. You can use the permanent link as you normally would when linking to another weblog. The Auto Discovery system recognizes if the site being linked-to has TrackBack enabled and if so, it automatically notifies the site via TrackBack. To add a little more to this mix, you can use a Movable Type Bookmarklet to make it even easier to manage- see the MT Beginner's Guide.
I see comments on weblogs all the time, why don't people just leave comments instead?
A TrackBack is like a comment, except the comment occurs on another weblog. Instead of leaving a comment, the weblogger posts a new entry on their site and sends a TrackBack notification to the original post, which closes the loop. This allows the weblogger to take the original post in a new direction and present it for their readers. This way, both weblogs benefit by having an explicit link between them, which enables visitors navigate between them easily.
Why would someone use TrackBack- what's the big friggin' deal?
I think a part of it is selfishness, and I say that playfully. Webloggers want compelling content on their web sites- they want to turn their readers onto something new. Also, they get a lot of inspiration from other webloggers and gain from participating in a community of webloggers.
Participation in this community takes many forms. One form is leaving comments on other weblogs- which contributes content to another person's weblog. A second form of community participation is TrackBack- which allows the weblogger to contribute to a discussion using their weblog instead of someone else's. In this way, TrackBack allows a weblogger to use their own weblog to actively participate in the community.
Why don't all sites use TrackBacks?
Most sites have the ability use TrackBacks, but not all do. My guess is that TrackBack and its advantages are not well understood among webloggers. Also, I would say that, like comments, not every weblog owner wants to have input from the outside world on their weblog. Further, most popular weblog tools can use TrackBack, but some do not "play well" with TrackBack.
More Plain English Explanations: