My expectation for this skill point is that with 10 intelligence I would get 10% poison penetration. After being disappointed by the node in general gameplay and somewhat suspicious of the wording used (it does not mention penetration or shred), I tested it on the Arena dummy. I tested this with a lot of healing effectiveness, so I was on full HP as this could potentially affect damage with other skill points.
My testing method was to just stand still, turn on AoD and let it run for a while (starting at full hp). I get roughly the same damage ticks specced into the node or not.
edit: i messed up with snapshotting HP