Facebook's widely adopted and somewhat controversial commenting system has always carried with it one giant drawback: a lack of support for mobile. That's all changed now, Facebook has announced on
January 12,2012 a plug-in for mobile optimized sites, paving the way for even greater ubiquity of the commenting system across the web.

Whether that's a good thing or not, we'll let you decide, but it will certainly make commenting on a mobile device a whole lot easier.       
According to Facebook, the new feature will use "social signals" to automatically detect the highest quality comments for each individual, with each thread ordered to show the most relevant and popular comments from a user's friends.

SOURCE:Facebook