I just purchased a Verizon Moto G (Android 4.3) to use for on-device Android testing. However, when I connect it to my 2011 MacBook Pro (running Lion), it does not show up in adb. I tried both running adb devices and using DDMS in Eclipse, neither of which showed any device.
I enabled USB debugging and I know that my cable works because when I set the USB computer connection to 'Camera', iPhoto launches and connects to the phone just fine. I also downloaded Android File Transfer, which also seems to connect.
I don't really know what other information would be helpful, and I've spent a lot of time looking for a solution to no avail. Let me know if I can add any information that would be useful.
Even though I didn't have EasyTether installed on this device, the drivers were still installed on my computer which was causing problems.
This solved it: http://intohand.com/blog/post/android-debug-bridge-not-just-working-on-mac