what is difference between trackback and linkback?
What is concept of ------
trackback
linkback
refback
pingback
Is trackback beneficial ? how?

Trackback means you can also go for the url provided in the list if the given link is not working properly. Link back it is the backlink to your site.

Link Back gives identical address of your site including Anchor Text that defines SEO purpose of your site! It has much worth then trackback

Trackback refers to comment on a remote blog. You can view trackback in blog after or before comments. If you have a blog try to use the feature trackback.

Linkback refers to backlinks or incoming links to your blog or website. There are so many ways to create backlinks. Some examples are Article Marketing, blog commenting etc