This is always a controversial topic - at what point do you spank a child and then teach them/parent them to be non-violent? This falls in the realm of "do as I say, not as I do" leadership.
I'm not opposed to spanking. Never have been. BUT, and here's the big BUTT, I'm against physical abuse of any kind, and especially of bullying. (Keep in mind the title of this blog).
My observation and personal experience is that parents resort to spanking when they have run out of options, or patience, for parenting and coaching. It takes MUCH MUCH more patience and creativity to come up with a discipline that is effective, than it does to swat a bottom. In essence, it is lazy.
Same thing, I believe, for the word "No". Seeing a child do something and just shouting from across the room, or from the couch, "No", when the best and most effective method would be to just get up and offer alternatives to the child - a "YES" choice.
It is interesting to note, though, that as we get to be adults, we begin to take classes on negotiation, or business, that invoke the idea of getting to yes, or win-win situations, etc. This is counter to the "No" "No" "No" parenting style. Just say "Yes", and then let's figure out how or what we can say yes to!
Just a thought, or two...