A trackback – is a word used mostly for search engine optimization purposes. In layman’s terms, when you post about someone else’s blog post elsewhere, your post will show up in their “trackback” section. It’s a very effective way for one to keep track of who’s linking and referring your posts. A permalink is used to create a trackback.
**Note: The trackback feature is not available with a Blogger.com account. However, if you are using WordPress as a blogging platform or website,trackbacks can be used to boost your search engine rankings.
Here’s a more technical definition from our trusted source wikipedia; A trackback is one of three types of linkbacks, methods for Web authors to request notification when somebody links to one of their documents. This enables authors to keep track of who is linking, and so referring, to their articles. Some weblog software programs, such as WordPress, CuteNewsRU, Movable Type, Typo,Community Server and Kentico CMS, support automatic pingbacks where all the links in a published article can be pinged when the article is published. The term is used colloquially for any kind of linkback.