You might want to disable Unity built-in 3-fingers and 4-fingers multitouch handling. Maybe you do not like how the touchpad/trackpad gestures are handled in Unity, or you just want to install Touchégg.
I have just updated my post to setup OS X-like multitouch gestures for Macbook Pros running Ubuntu. It should now work for any modern Ubuntu release, from 12.10 to the latest 13.04 Raring Ringtail. In order to disable the arbitrary default multi-touch gestures on any laptop, follow the instructions in section 2, Disable Unity built-in gestures.
Read it here.