Seatpins - what does zero degrees mean?

[fearby]

I am a bit confused about setback and "zero degrees."
Are they the same thing? Apart from a zero setback seatpin moving my saddle forward a bit what other properties will it give?
Just got a new bargain carbon bike with poor saddle and seatpin which I am looking to replace. The seatpin has a lot of setback and so the saddle looks like it is shoved too far forward (not a good look).

 

[Peter@vecchios]

I am a bit confused about setback and "zero degrees."
Are they the same thing? Apart from a zero setback seatpin moving my saddle forward a bit what other properties will it give?
Just got a new bargain carbon bike with poor saddle and seatpin which I am looking to replace. The seatpin has a lot of setback and so the saddle looks like it is shoved too far forward (not a good look).

The attachment clamp, etc is directly above the seat pin shaft rather than aft of it(most seatposts). On some like Thompson, it uses the same clamp, but bend the shaft aft for 'setback'. That's all it does, allow you to move your saddle farther forward. Used for slacker seattubes when you 'may' need to get to that small 'c' constant of KOPS(Knee Over Pedal Spindle).