In a recent update, Facebook launched reply to comments system. Read this post for more info about threaded comments on Facebook.
I was just in middle of my routine browsing when I saw something new at a fan page. I could see that people have replied to some comments also. According to the research which I did, I could see that this has not been launched all over Facebook, though I could see it on a Fan Page, but as soon as I navigated back to my profile to see whether it was there for my status updates too, I could not find this. So I could conclude one thing, that Facebook is just testing it in beta stage for some of the fan pages and groups, if they get a positive response, then this will be launched all over Facebook in next few hours or days.
There was news about the threaded comment system since a bit of time, people were actually demanding it to make it more interesting while spending their time on Facebook. This will be a Good move by Facebook. For example If any of your friend have commented on your status and you got 10 more comments after that, then it adds no value replying to his comment after 10 more comments, now using this system, You will be able to reply directly to the comment you want, this will give an extra advantage and quality to the discussion happening at certain place on Facebook.
This will not be a multilevel comment system, however it will be two level. For example, you can reply to a comment, but then further no one can reply to the comment you posted as reply to another comment. This will stop the complications which might be caused due to the multilevel threaded comments. As I told, this has been launched for just testing purpose, so it might take a bit of time before you see it on your profile. If you want to experience this, you can click here to go to a Facebook Fan page and see that yourself.
I hope this post was useful. let me know if there is something you want to share with me. I will be waiting for your comments. 
About Kunwar Prithvi Singh Chauhan
I was waiting for it since a long time, thanks god they launched it. It will be interesting to have a discussion over Facebook now. Thanks for Sharing
Thanks rocky. And I am sure It will make discussions even more interesting now.. Thanks for your comment.
Spamming makes everything bad.
Yeah it does, but it can surely be a great way and it can change the way how people communicate over facebook comments. I see a lot of positives in it..
Hope people will not use it for fighting and abusing each other.
Yeah, we can just hope.. Nothing else..