trackback is simple a link back to your website. Its a method for website authors to request notification when someone links to their post or articles on the web.It can be really useful in tracking who is linking to your articles or post.
Trackbacks can be good and bad. Some one can put spam links(this is similar to spam comments) in your track back which can eventually result in downfall in your google ranking.
You can use trackback spam filters which is mostly available on most of the blogging platform now a days.
You can see whether the site providing trackback is good or not. If its not good you can remove the trackback.
Hope this helps.
Have a great day.