Basically, you use it to ping another web log. You ping a specific URL and then you automatically link to someone elses blog and they link back to yours. (I'm pretty sure that's how it works).
That's right. When you see a story on another blog that you want to write about, you ping the other persons weblog.
That got me thinking too... so here's HaloScan's trackback faq. It also includes a link to SixApart's (Moveable Type) Beginner's Guide to TrackBack
No worries, dude, and here's Haloscan's illustrated trackback ping tutorial too I have to admit I've not used trackback because my blog is purely Blogger and they state that "Blogger does not currently support Trackback." I've also not used the HaloScan service because my major concern is potentially "losing" all the wonderful comments on the blog so far... If Blogger can get enough feedback (use their talk to us link) asking that trackback be incorporated into their system then they might do something about it
Just for the record, although Blogger don't offer TrackBack... Haloscan do... Added - Sorry, I didn't mention that the trackback is designed to work with Blogger Blogs... http://www.haloscan.com/
I installed the Haloscan trackback/commenting system on a few of my blogs. After using it for a while, there are somethings that I just don't like. Their comment "manager" doesn't distinguish between sites you have it installed on, so when someone leaves you a comment (or worse, spams you like someone from here did!) then you have to go and figure out where the heck they left the comment lol. I think I am going to remove it as I have not had the time to really get into the trackback stuff and the Blogger commenting works fine for me. Maybe if I could understand the trackback better and why it is so different from leaving a comment with a link, I would see the light.