Trackbacks are helpful for three primary reasons:
Reason #1: It tells the author of the original article that you're continuing or expanding the discussion on your blog.
Reason #2: When you Trackback, a link to YOUR blog appears on the original author's blog, if they accept your Trackback. Not only are you sending traffic to the original author, they're sending traffic back to you! (Notice how many people Trackback to Seth Godin's blog? One reason people do it is for the traffic.)
Reason #3: You make friends. I've found that to be a successful blogger, you must become friends with other successful bloggers. One way to quickly "make friends" is to send Trackbacks.
For Typepad or Wordpress, it works like this:
Step #1: Write a post on your blog that references a post on another blog.
Step #2: In the body of your post, create a link to the original blog post that inspired you. (The link must go to the specific post, not the home page.)
Step #3: Underneath the space where you write your blog post, you'll notice a small box that says "Send a Trackback to these addresses" (Typepad) or "Trackback a URI" (Wordpress).
Step #4: In this space, you'll want to copy and paste the Trackback URL. If the person you're linking to uses Typepad, you'll notice that underneath the original post, there's a line that says: "Trackback URL for this entry." A URL like this follows:
That's the link you want to copy and paste into the "Trackback" space underneath your new post in your user interface. Now, if the person you're linking to uses Wordpress, then the Trackback link is almost always the same as the normal URL, except you add "/trackback" at the end.
For example, you would link to:
And then you would send a Trackback to:
Does this make sense? Give it a try and see what happens. Heck, Trackback to this article if you want. After all, the more people who know how to do this, the more Trackbacks you're likely to get!
Now, after you complete the steps above and publish your post, please double-check your work. Go to your blog and click on the link to the original author's post. Does it work? If not, go back through the steps and see if you can identify where you made the mistake.
A common error is to link directly to a Typepad Trackback link instead of linking to the permanent URL. This won't work. You've got to hyper link to the permanent URL... and then ping the Trackback link. So there are two links involved. You cannot send a Trackback with just one link.
When Should You Send a Trackback?
It's my belief that you should only send a Trackback when you're adding to, expanding, or continuing a discussion. This way readers can track how a discussion evolves from blog to blog.
If you are only giving a one-sentence plug to a great blog post you found, then you should NOT send a Trackback. In this case, simply link to the blog post without sending a Trackback. (Otherwise, it might look like you're trying to hijack traffic from the original author's blog without adding any value to the discussion.)
P.S. When somebody sends a Trackback to my blog, I see it in my user interface. I can accept the Trackback if it's a legitimate post. I can reject the Trackback if it's a spam post. This is why you often won't immediately see your Trackback on the original author's blog. Don't worry if this happens. Just wait a few hours and check again.
P.P.S. In case you're wondering, Blogger doesn't have Trackback functionality, which is one reason I don't suggest using it.