Now this is very tricky thing. I have recently seen that many blogs do have facebook comment plugins where anyone can comment and place relevant links.
But the problem is those links are in text and are not hyperlink or you can say not clickable.
I found here in this article post right down you can see a facebook comment plugin, there you can see a text link is a hyperlink. http://www.huffingtonpost.com/2014/11/25/black-friday-apple-deals-2014_n_6211754.html
Now my question how did that user do that? i mean from text to hyperlink. Becz normally it won't happen. I have searched lot of stuff in google but i am not able to get the correct method.