Facebook is testing a new feature for comments on statuses. The new feature would allow users to thread off and reply to a comment instead of having to reply to the main status. It's similar in function to some of the bulletin boards and comments systems that you've seen around the web, except it will only allow you to go one level deeper.
In other words, a comment upon a status can be both liked and commented upon, but those subsequent comments cannot be commented upon. Facebook has said that at this stage, it is just a small test, so you likely won't see the option. But if you do, be sure to check it out and let us know what you think of the feature.
"We are testing a new way to add comments to a post on Facebook. With this test you will be able to reply to another comment as well as the original post," a Facebook spokesperson said. "This is just a small test at this stage."