According to
http://forum.cyanogenmod.com/topic/3...hite-vs-green/
Network status icons turn green if you have a Google Account added to your phone
and the phone is connected to Google services, for syncing your Gmail, Calendar
events, contacts, for backing up your settings, and so on. If you don’t have a Google
Account or if, for example, you’re connected to a Wi-Fi network that is not connected
to the Internet, the network icons are white