Jabber, the FB message notification system doesn't always work well. I've often missed (unintentionally) messages sent to me. If I have a lot of notifications, and just click on the message icon to see who sent them, it doesn't automatically take me to the messages, it just gives me a list of who sent them. So I often get busy and distracted and forget to go back to READ those messages...I feel badly when I do, but in my experience, most people understand because it happens to them too.

If you've only sent one message to a friend and they haven't responded, perhaps that's what's been happening. If you've sent several to one friend and haven't heard back, then that's a different scenario. If that happens to me (and it does), I just figure they either don't have anything to say, or are too busy and don't have time to respond. If it's serious, I'll send another one saying that I need an answer. If it's not serious, I just let it be...let "other" be "other".

Don't know if that helps. I do know that if someone sends me a message that puts me in an awkward situation, e.g., over an issue that I might have a different opinion about, and I don't know how to respond, I don't answer right away. I'll sit and think about how to answer.