Everyone refuting this is missing the point. No one, not even geeks would realize you have to specifically de-activate iMessage before you switch to any other

Everyone refuting this is missing the point. No one, not even geeks would realize you have to specifically de-activate iMessage before you switch to any other phone. This exact thing happened to me. I switched back to Android and after a week of not receiving messages from my friends and family it took me hours and quite a few calls (sadly) to both AT&T and Apple before it was figured out. In fact at first Apple had denied that anything should be wrong, thus all the wasted time figuring this out. Left a really poor taste in my mouth from the whole experience.