i think kpop is popular is because their concept and their songs are different from each others... yea they have the similarities here and there but it's not all the time like american songs... i admit i like american songs too but i LOVE KPOP more and also kpop is more popluar is because kpop has more beat to it to where you can dance to it more then american songs... not only that but kpop has alot and i mean A LOT of HOT KOREAN GUYS!!! -ahem- and girls... ;) you know what i mean~ hehehe i rest my case here

:')
I think it's popular because their MV concepts and everything are so much different to what we see usually
and the fact that we can feel a more personal connection to the idols since they devote lots of time to fans~