Well, I guess I'm going to have to be the voice of dissent on this thread. I pretty much agree with the article. The rule in our house was take it outside. I think there's an honest bluntness that exists between siblings that is not found anywhere else in the universe - I believe it is the direct result of the fighting that took place as they were kids, but in the end they always made up.
Today, my adult children all get along. The two sons (a year apart) who fought so much we had to switch their bedroom are probably as close to each other as any two I've got. They work on each others houses, and just last summer worked together on building their decks.
If your children are comfortable with each other now, then obviously what you did worked for you. Each family has its own dynamic. I thought this description from the article,
... out-of-control boys who do nothing but argue, fight and generally wreak havoc wherever they go. was just illustrating the results when a parent is too weak to discipline.
Even if your boys fought one another, I doubt that you let them "generally wreak havoc wherever they (went)."