placing damage counters

[cattdreams]

I was just reading the most recent posted rulings and that placing damage counters is an "effect" of an attack, does that mean that machamp with it's immunity and dustox which has a power thats similar (prevent all effects of attacks) can ignore anything that places damage counters?

[Big Daddy Snorlax]

We got an answer to this back in September, but we didn't get it posted to the question. Here is the answer, courtesy of the Compendium:
== ATTACKS

Q. I've noticed that some cards say "Does 10 damage to the Defending Pokémon", whereas others say "Put 1 damage counter on the defending PokÈmon". Is there any reason for the different wording? I've spoken to someone who says that you do not apply weakness or resistance for attacks where it specifies Damage Counters; is this the case?

A. There is a difference. As you mention, weakness and resistance are not applied when placing counters. Also, things like Defender and Metal Energy will not block Placing Damage Counters. It will not trigger things like Base Set Machamp's Strike Back. In the steps of resolving an Attack, "placing Damage Counters" counts as an Effect of the attack, it is not part of "doing damage". (Sep 18, 2003 PUI Rules Team Meeting)