I began reading a book called “The Orthodox Way” by Bishop Kaalistos Ware, and in it it said this about deification of man:
“By virtue of this distinction between the dicine essence and the divine energies, we are able to affirm the possibility of a direct or mystical union between man and God ---- what the Greek Fathers term the theosis of man, his “deification”-----but at the same time we exclude any pantheistic identification between the two: for man participates in the energies of God, not in the essence. THere is union, but not fusion or confusion. Although “oned” with the divine, man still remains man; he is not swallowed up or annihilated, but between him and God there continues always to exist an “I----Thou” relationship of person to person.”
I think what the original poster who cited Eastern Orthodox believing in man becoming a God, is maybe having trouble with the context and the use of the term theosis of man. Eastern Orthodox Christians do not believe in becoming Gods, but becoming united with God, and of course eternal life like the rest of us do.
You would be better pressed going over to an Eastern Orthodox board and getting an explanation.