Hopefully somebody more historically vested in Motorola devices can chime in here (it's been since pre-Android that I owned a Moto-Device). Android use has been limited to Windows phone(s) dual booting to Android, plus work I've done to root/load Android on wife and daughters Nook-En-Droids.
Razr M was my jump-in point for committing to Android on a daily basis to handle all my MS-Outlook and MS-Office requirements on a phone.
So, I've been seeing different colored LED light colors emitting from the upper left-hand screen (left of the silver Motorola Badge on front side, and left of what I believe to be the light sensor). I've asked others to look at LED color (including Verizon reps) and they say it's just my eyes, the light is green either on/off. I see Green normally, but sometime looks Blue, even though others say it's green ...?
My guess so far is there are multiple different color notifications (maybe more based on device setup ...?):
LED On = New Notification
Green = Email, Calls, Txt's
Blue = Facebook & maybe various other "Social Network Msg's (Facebook, TwiDroid, Google+, LinkedIn, MySpace, etc.)
Red = Low Battery (thanks calbrs04 - forgot that one)
White = While charging, indicates not enough power to turn on.
I would appreciate and additions and/or corrections.
PS: as additional LED colors and/or notification indicators are posted, I will update this OP#1 (along with credit to appropriate member) as a way of consolidating the related info into one location for future viewers.