For some reason, I opted to change my commenting system. But this isn't for good though. I'm still thinking it through. But for now, it's kinda cool to have this new comment box.
I changed this a few days ago and already I see some advantages and disadvantages.
1. Possible viral effect. This has a built-in LIKE function for the post. If people click it or if they leave the checkbox at the bottom ticked, the action is going to be published on their Facebook profiles and will be seen by their friends in their news feeds.
2. Comment spam reduction. This is still vulnerable to manual spamming. But it's very likely that spammers will use their real Facebook accounts just to spam. Sure they can create a dummy account but that obstacle should reduce the amount of spammers significantly as very few blogs/websites are using this comment system.
3. Less trolls / flamers. This is due to the same reason as above. People cannot hide behind anonymity anymore.
1. Comment moderation. As far as I know, there is no way to moderate comments before they are published. You have to check posts every now and then and remove any undesired comments. This is very troublesome for big and popular blogs.
2. Less comments. Some readers might not be comfortable revealing their identity or their Facebook accounts. Some will opt to not leave a comment at all. Some also leave comments for the sake of leaving a link to their blog/website. While this is spammy in some way, a lot of times these bloggers or webmasters still have something important to say.
3. If you have other (the older ones) Facebook elements on your website, doing this might mess those up. For example, if you have an old Fan Page box in your widget or elsewhere, putting in the Javasxript SDK needed for the comment box will mess that up. You have to make sure that all Facebook Social Plugins you have are up-to-date.
4. You will naturally want to close / disable the old commenting system and depending on what platform you are using, you might need to hide all previous comments. Not cool.
Here is How To Use Facebook Commenting In Blogspot if you want to try it out.
One of the top reasons why I am reluctant to implement this for good is because I implement a dofollow commenting system on this blog.