This field allows you to notify other blogs that you may have referenced in your post of your content. For example: if you have quoted an article written on another blog in your post you can enter the address of the other blog in this field and they will be notified of your post. This is useful for building incoming links to your site. If you enter more than one web address (or URL) separate them with a space.
NB: You should consult your web developer or IT Department before using trackbacks.