The Difference Between Trackbacks and Pingbacks

Ever wondered what the difference is between a trackback and a pingback? They both let you know when someone else has blogged about one of your posts, and the terms seem to be used interchangeably at times — so what’s the deal?

The WordPress Codex’s Introduction to Blogging article has a good explanation:

Trackbacks were originally developed by SixApart, creators of the MovableType blog package. [...] Most trackbacks send to Person A only a small portion (called an “excerpt”) of what Person B had to say. This is meant to act as a “teaser”, letting Person A (and his readers) see some of what Person B had to say, and encouraging them all to click over to Person B’s site to read the rest (and possibly comment).

[...]

Pingbacks were designed to solve some of the problems that people saw with trackbacks. There are three significant differences between pingbacks and trackbacks, though.

1. Pingbacks and trackbacks use drastically different communication technologies (XML-RPC and HTTP POST, respectively).
2. Pingbacks support auto-discovery where the software automatically finds out the links in a post, and automatically tries to pingback those URLs, while trackbacks must be done manually by entering the trackback URL that the trackback should be sent to.
3. Pingbacks do not send any content.

So there you have it: pingbacks can be automated and don’t send content, whereas trackbacks are manual and send an excerpt of the initiating post.