Notifications are not vibrating I got my Samsung Galaxy S2 (android 4.0.4) for a few days now and i realized there's something wrong with the vibration.
When I get whatsapp message or Viber, facebook, or email notification the phone won't vibrate! 

When I receive a call or standard text the phone does vibrate. I did a hard reset but the problem still remains. What do I do? 

In settings, it is ticked sounds and vibrate.

Please help
I had the same exact problem, and it was driving me crazy! 
Sadly, I couldn't find any solution other than to install an app, "Sound Manager": selecting "whenever possible" in the vibration settings the vibration will work just fine!