How to boot someone? Send more water to the person than the person can get out, once the water gets full it over spills and the person is booted, now at yahoo's end when you send an instant message to a user yahoo takes that packet then delivers it to the client now if that client is busy, instead of throwing away that packet yahoo stores it in a buffer (buffer is like a swimming pool, you can fill it but not too much or it will overflow) now as you keep sending on packets unless the client is awake and able to get them the data will get stored in the buffer and it will keep getting stored in the buffer until the buffer is reached when this happens yahoo assumes the ID is no longer active so yahoo disconnect the ID.