Ohh yeah! Sorry. You know what it feels like when you get an e-mail or an instant message. It's a full vibration. A half vibration is exactly what it sounds like
It vibrates for half the time! So it's a quick little vib that you feel. I honestly think that for IMing, which for me is ... pretty frequent, that it should use a half vib. It feels better.
Just download IM+ and you'll see ;) it's wonderful! But JT kicks a$$! It's way better application wise.