Smooth scrolling - where does it come from?

This was answered in-depth on the Crunchbang forums, they describe this scrolling as "smooth inertial scrolling."

One has to configure the touchpad driver correctly, and the example given, which sounds like it could be universal enough to configure yours as well, uses the package synclient.

They've used these settings in synclient, I've linked the man page, above:

Parameter settings:
LeftEdge                = 1752
RightEdge               = 5192
TopEdge                 = 1620
BottomEdge              = 4236
FingerLow               = 25
FingerHigh              = 30
FingerPress             = 256
MaxTapTime              = 92
MaxTapMove              = 76
MaxDoubleTapTime        = 180
SingleTapTimeout        = 180
ClickTime               = 100
FastTaps                = 0
EmulateMidButtonTime    = 75
EmulateTwoFingerMinZ    = 282
EmulateTwoFingerMinW    = 7
VertScrollDelta         = 100
HorizScrollDelta        = 100
VertEdgeScroll          = 1
HorizEdgeScroll         = 0
CornerCoasting          = 0
VertTwoFingerScroll     = 1
HorizTwoFingerScroll    = 0
MinSpeed                = 0
MaxSpeed                = 1.22754
AccelFactor             = 0.0615836
TrackstickSpeed         = 0
EdgeMotionMinZ          = 30
EdgeMotionMaxZ          = 160
EdgeMotionMinSpeed      = 1
EdgeMotionMaxSpeed      = 401
EdgeMotionUseAlways     = 0
UpDownScrolling         = 1
LeftRightScrolling      = 1
UpDownScrollRepeat      = 1
LeftRightScrollRepeat   = 1
ScrollButtonRepeat      = 100
TouchpadOff             = 0
LockedDrags             = 0
LockedDragTimeout       = 5000
RTCornerButton          = 0
RBCornerButton          = 0
LTCornerButton          = 0
LBCornerButton          = 0
TapButton1              = 1
TapButton2              = 0
TapButton3              = 0
ClickFinger1            = 1
ClickFinger2            = 1
ClickFinger3            = 1
CircularScrolling       = 0
CircScrollDelta         = 0.1
CircScrollTrigger       = 0
CircularPad             = 0
PalmDetect              = 0
PalmMinWidth            = 10
PalmMinZ                = 200
CoastingSpeed           = 30
CoastingFriction        = 30
PressureMotionMinZ      = 30
PressureMotionMaxZ      = 160
PressureMotionMinFactor = 1
PressureMotionMaxFactor = 1
GrabEventDevice         = 1
TapAndDragGesture       = 1
AreaLeftEdge            = 0
AreaRightEdge           = 0
AreaTopEdge             = 0
AreaBottomEdge          = 0
HorizHysteresis         = 25
VertHysteresis          = 25
ClickPad                = 0

...and added this to autostart:

    ## Detect and configure touchpad. See 'man synclient' for more info.
if egrep -iq 'touchpad' /proc/bus/input/devices; then
synclient VertEdgeScroll=1 &
synclient TapButton1=1 &
synclient CoastingSpeed=35 &
synclient CoastingFriction=30 &