If one more confused user mails the list and asks why they have 6 mozillas or 4 nautiluses, I think I'm going to go insane. ;-) It should really display a multithreaded app only once. Or at least somehow indicate that the threads are only threads.
Until glibc's threading is changed to actually use the Thread GID's the kernel provides there's no point in top also using them..... And there's no other way to find out if 2 proccesses happen to be a thread.