I discovered that you can raise and lower the sound volume in iTunes by moving 2 fingers on the trackpad right & left 
I am sorry if its old news, but its my first mac so bear with me
and if you are interested then add your discoveries..
I think all know those for the images already
1) Safari Scroll page up/down = Move 2 fingers up/down
2) Safari Page Back/Forward = Move 3 fingers right/left
3) iTunes Volume up/down = Move 2 fingers right/left
I am sorry if its old news, but its my first mac so bear with me
and if you are interested then add your discoveries..
I think all know those for the images already
1) Safari Scroll page up/down = Move 2 fingers up/down
2) Safari Page Back/Forward = Move 3 fingers right/left
3) iTunes Volume up/down = Move 2 fingers right/left