I say you don't stop fighting until the ref stops you. However, there are some cases where it's obvious the fighter is done, so you should not follow up with strikes.
On the other hand, sometimes people play it off like the fights over which is even worse IMO. A good example is Thiago vs Koscheck... although I think the stoppage was good, I bet it would have lasted longer if Thiago went to the ground with him instead of just doing nothing and acting like he already won.
What a stud
The power of Aleks, his small baby and pimp hardcore dogs has granted you useful insight, my friend.