I was trying to do a search on my phone, when I noticed that in Google Now, the filler text said “Search, or say Ok Google”. That was surprising, since when did that come about? The previous hotword or activation phrase was just plain “Google” with the language set to US-EN.
A quick search on the Interneck revealed that a roll out happened around 25 Sep 13 and this was one of the changes. You will need Google Search app 2.8.7 , mine was 2.8.8. This brings the hotword activation nearly in line with Moto X. “Ok Google” vs “Ok Google Now”.
The really nice result of this change is that the hotword detection works even in the search results.
Try saying “Ok Google” twice. It displays all the possible uses of Google Now.
Further testing reveal that this update disables playing of music local to the phone / handset. Play and Listen command returns web results instead of launching the default music player. The list of apps in the Google Now Settings does not show any music player either.
Update 25 Apr
To get Google Now to play locally stored music, you need to have the app Google Play Music. This app will play both local and Play Store music. I found that this app was a RAM hog and I have since uninstalled and use Rocket Player. Live and let live.