A quick and dirty way, which would also eliminate legitimate users to some extent, would be to store a domin cookie called say 'lastpostedAs' and save their memberid when they post,
then when someone posts, you could check their currentID against the one in the cookie, and do what you wish if they are not the same
basically when you go into a thread/topic the boss is asking for the topics/threads with the latest infomation or updates shown at the top even if they are nto new threads.