Quad and circular polarization

Greets OMs,

yesterday i had a QSO with K2US - impressive antenna, by the way i'm using

the station of a local OM near my QTH with a 4 elements 5 band Quad.

The beautiful thing is the 9-9+20 signal around 20.45 UTC, far away in 
magnitude from the others stateside signals, around S5-7. So i remember my

father that tell me one day in his opinion the circular polarization in
the 
better choice... lose no matter about 6 dB, with any kind of polarization 
used at the other side except circular - and faraday torsion due to 
ionosphere - and in my mind comes 2 questions...

- we take some advantage from the fact that both are using quad antenna ??
- in my non-knowledge of the facts, i have in the past believed that the 
quad antenna is near a circular-polarized antenna. Reading books and
hearing 
some QSO in the air i learn that quad can be horizontal or vertical 
polarized, regard the feed point of the quad.. so - the circular 
polarization need some kind of "special" feed point or is merely a
"circle" 
antenna ??

Apologize for the english and for the questions, maybe trivials and
stupids, 
but i believe one esxperienced OM can say far better than 100 books.

73,
CQ -.-. --.-