It is absolutely not true that pups do not understand a time out. I have used it successfully in a few cases.
One is a biter that came to me as a feral dog...living in the woods. He was wild...and would attack the other pups when scared. He bit me a few times in the beginning. Whenever he would do something such as attack another pup, I would put a crate right up to him and say "kennel up" .. could have been "time out" or any other words. He would stay for a few minutes and then I would let him out. I had to do that many times...and eventually I graduated to "time out" in the bathroom. It worked! He responded...he quickly figured out that if he did something that was not acceptable, he could not stay with the rest of us. It was kind of cute....after some time, all I had to say was "kennel up" and he would run for a crate or the bathroom. He totally understood!
As for those of you who think that is punishment and they will never like a crate, that is also not true. Matty had surgery this past year on his knee and had to be crated ...and to this day he still goes to the crate to sleep. I have open crates in my home and they all go in them from time to time. I don't believe in "punishment"...I believe that a time out is not punishment, but rather discipline and direction.
I have two females who used to bicker and fight...(they still do once in a blue moon)...I used time out for both of them. One in one room..and the other in another room. It only takes a few minutes. At first they would come out and start again..and I would put them back in their rooms. They got it! Behave and you can stay with the rest of us...don't behave and you can go off to a room by yourself.
Pups love to be with us....removing them when their behavior is unacceptable DOES indeed work. You just have to be consistent.
In the case of the sofa, not so sure it would work for that. I just wanted to comment on all of the remarks made about pups not understanding time outs.