It's from VZW email sync service. VZW automatically signed you up for this. I got this too after installing CM7. You need to log into your VZW account. Look for the email sync service and disable the service. Once it gets disabled you will get another SMS with STOP in it showing it was disabled.

 

I am faced with this issue every once in a while when I install a new Rom. I call Verizon and ask them to remove the service since I never signed up for it.
For some reason I get more satisfaction from verbally telling them I don't want it, never signed up for it, please don't sign me up for things I didn't ask for.

 

That's funny!

 

for whatever reason I've only seen that on the AOSP ROMs. None of the Sense ROMs did it. I installed a firewall after having to deal with VZ to take it off the first one. I know MIUI, CM7 and Liquid all did it.

 

If you disabled this from the VZW website you should have gotten a similar message sent to you but with the word "stop" in it.

 

heres an article on it with steps to remove....

Incredible 2 Owners Receiving Text Messages from VZWNMN? Here is How to Stop Them – Droid Life