I'm not positive this is what you are talking about. Are you referring to the "comment" box when you set a status from the suggestions list? If you are, when I start typing a comment, my browser retains what I've used before and automatically comes up with a comment hint or hints if I've type the same comment previously. The box of comment hints I think is generated from the most used comments from the previous week (maybe month). What I'm seeing is held in my browser cache.