CyanogenMod is a popular custom ROM for several Android users and it now offers a new way to update to the latest custom ROM. Instead of using the ROM manager for updates the newest nightly builds of CyanogenMod 10 now include the CM Updater.The CM Updater adds a new option to your settings menu which allows you to download the latest updates OTA (Over-the-Air) just as they would regularly update Android.
The CM Updater doesn’t support features of the ROM Manger like flashing custom recovery or downloading add-on install, so the ROM Manager method will be around for a little longer. However CM Mod users who doesn’t upgrade their ROMs regularly will be happy with this user friendly method.
source – CyanogenMod