Where does the gravity go?

with string theory they are talking about gravity being a particle; graviton. More so it is a closed loop string that freely moves between all dimensions (all 10) and therefore is hard to study in our 4 dimensional space.
Im not sure though how gravity being a particele add up with the "pull" of gravity. Is gravity then an exchange of particels between objects just like light is "given" from the sun. And how does this differ from Newtons idea about gravity being some kind of force tying objects to each other?