As far as I can tell all of these (except the last one) are sincere expressions of belief by Christians - but they are all different.
'The whole point of Jesus' incarnation was so that he could be punished on behalf of all humanity, a feat he accomplished through being crucified.' (this is the same as the explanation I posted in my blog yesterday)
'The reason Jesus died (according to Christian theology) was so that he could overcome death and be resurrected. While the atonement made possible the expiation of human sins, the resurrection made it possible for immortal existence.' (not sure what this means, but I think it's different from the previous)
'A suffering God was easier to relate to, and showed the people that God did not despise them for their suffering but was with them in suffering.'
'A good, kind person can easily start wondering, why? Why must I suffer when I try to be good and kind? Is God punishing me? Well, even God suffered. God suffered so much because God loved us so much. God understands our suffering, is there with us through it.' (this person sounds really nice, if you read his whole post)
'The fear of eternal death and damnation, symbolized by the cross, loses its grip on Christians because Jesus already suffered and died for the rest of the world.'
'I must plead some ignorance to understanding but it sounds a lot like: God began to wonder if he screwed up with us so he came down as a human and lived among us to find out what our life is like. Then, he let us stomp the crap out of him and kill him. Just God's way of saying, "Sorry, all is forgiven," or something.'