It vibrates everytime the screen registers a touch. It is very light. When I first starting using my N900, I got the initial impressiion that the build quality ws bad. I thought the slider mechanism was creaking every time I touched the screen. Eventually I got clued in as, the slide out seems solid and my squeeze test didn't reveal any creaking or twisting. After using the N900 for 5 days, I think it's a great feature. It gives some solid feedback when interactive with the device.