The term PING is used to state that your blogging program (like Writer.. See the tools page) will tell another program (like Technorati, though there is a metric butt ton of sites out there that do the same thing) that you have posted a new entry to your blog.    More or less it’s like a search engine, only faster.  Where as you need to wait for a spider like Google to crawl your site and add your post(s) to the index, since you are telling the index that you’ve added a post it’s up almost instantly.

On the other hand, a trackback is a way to try to have two blogs engaged in the same discussion threading their discussion so that someone who stumbles upon one weblog will see the conversation continued on the other.   The theory is that two bloggers can hold a conversation on each others blogs but still have those two blogs ‘linked’ together though the trackback.

However, there’s a problem here.  Spammers (of course.. *sigh*)  whom quickly figured out that they could use the trackback to their porn site to generate more hits.  Therefore, most bloggers have the trackbacks turned off.