The fact that this API is one-way really highlights the difference between Facebook and Twitter.
It's one-way because Facebook has to be worried about spam since anyone can send a message to anyone else. Twitter doesn't have this issue because you have to opt-in before you ever receive a message from someone.
It's one-way because Facebook has to be worried about spam since anyone can send a message to anyone else. Twitter doesn't have this issue because you have to opt-in before you ever receive a message from someone.