The CyanogenMod team has recently merged a new feature into their Jelly Bean code called Quick Message, which displays a popup notification when you receive a text message. The popup includes the ability to reply from the popup, swipe to other messages, view the message in your SMS app, and dismiss the notification.
Quick Message was built by developer David van Tonder and added to CM10 nightlies a couple of days ago. Yesterday, van Tonder and CyanogenMod announced an update that adds a Quick Reply option to the SMS notification in Android’s notification shade. This option is only available if the Quick Message popup is disabled and if the message is a single SMS or a thread from the same sender. CyanogenMod says that the feature is still in progress, so there may be bugs, but if you’re installing nightlies, you’re used to that.
source: android police