What is RSS?
RSS (Rich Site Summary) is a format for delivering regularly changing web content. Many news-related sites, weblogs and other online publishers syndicate their content as an RSS Feed to whoever wants it.
A ping is what happens when one software program notifies another one of an update. It’s basically an electronic way two software applications or computers say “hello, here’s what’s new.” In computer networks (and the internet) one computer can ping another to see if it is online and active. It sends out a signal, or, “ping” over the network to see if it reaches anything. Think of sonar pings from an old war movie, or something, and you get the idea.
When you come across a blog post that inspires you to write your own blog post, or which you want to cite, you can manually create a kind of link to it known as a trackback. It’s called a trackback because the link “tracks” back to the other blog. When you create a trackback, the blog that you’re tracking back to will be notified. How is it notified? It’s pinged, naturally! When you are writing a post in WordPress 2.5.1, you see the trackback area (pictured below) beneath the writing window.