I don't much like using AIM to talk to people on the hall. Sure, it's convenient, and less intrusive then going to their door, and an Away message is a better guide to whether or not someone is available than if they're capable of answering their door. But I don't like it because I spend enough time in front of this computer, both for good reasons and bad, and I much prefer my interpersonal relations to be with people.
But OTOH, you can chat on AIM while naked or otherwise incapacitated, or with a room so messy you are incapable of offering someone a place to sit. So it does have its good points.