Trackbacks and pingbacks allow you to notify pages on other websites that you linked to them from your page.
Trackbacks and pingbacks are very similar, they are like remote comments.
Both websites should have enabled trackbacks and pingbacks.
Trackback is old technology.
Uses /wp-trackback.php file.
Trackbacks use HTTP POST communication technology.
Users rarely use trackbacks because it is require extra input. Spammers uses trackbacks because it is easy to cheat here.
Trackback needs to have a URI entered manually.
You don’t necessarily have to link to an article to send a trackback.
You can find the option to send a trackback at the bottom of each new post.
Check out "Screen Options" tab ("Send trackbacks to:" option) while editing post.
Just copy and paste the link to another article and you’ll send a trackback. - http://www.site.com/post-url/trackback/ ("/trackback/" is added to the post address).
How trackback looks in comments section (notice the page title in strong tags) (html markup is removed from content):
Pingback is newer technology than trackback.
Uses /xmlrpc.php file.
Pingbacks work automatically.
Pingbacks use XML-RPC communication technology.
The pingback automatically finds URI’s in the post and pings them.
Pingbacks differ from trackbacks because you have to actually link to the article within your post to notify the author.
Users use pingbacks very often because they work automatically. Spammers does not use pingbacks (because it is hard to cheat here).
How pingback looks in comments section (notice the dots in square brackets) (html markup is removed from content):