Blender Git Commit Log

Mac OS X 10.7 supports new trackpad (and mighty mouse) events with nice seamless
scrolling and inertia.

Now Blender uses this - if you have 10.7. Otherwise it just falls back on the
old code.

Try it, makes a huge difference :)

Next todo: how to configure this well, so you can have trackpad (or mighty mouse)
zoom as default in 3d views.