<Snipped quote by Mokley>
That's actually a really interesting point of view. However, it'd also mean said people would miss out area type events. For example a big fight happening in a classroom but they never noticed it because their in a conversation and they they didn't read the posts of others.
This is where the GM comes in. In this case, as GM I'd mention that "Shouting and crashing in the next room drowned out their conversation," and then maybe quote some pieces of the shouting characters' posts that the eavesdropping characters would understand through the wall.
In one RP situation, for example, there was an intercom system with input/output in multiple rooms. Virtually no one heard anything that PCs said over the intercom until the GM repeated it all at once, loud and clear, for everyone to hear. PCs immediately acted upon it.
This is essentially the GM repeating what the players have already posted, formatted and reworded in a way that relates to each individual character. Logically you might think that the players would ignore each other completely in this case, but I've only seen them pay MORE attention to each other's posts when they see how much each character's actions affect the scene and story.