John, I am going to disagree with some of what you have said there. I think you might be confusing cause and effect.
DMOZ & Google share data, cool it is a done deal, so why would they penalise themselves or their directory partner. As for all the other sites, Google seriously attacked DMOZ clones a year or two back, and while you can get away with puling niche data from DMOZ, if you copy large chunks, you will eventual;ly get pinged.
Duplicate content has absolutely nothing to do with using the same titles etc, it is the un-natural linking pattern algo that gets triggerred not a dup filter.
And it IS possible to harm a competitors ranking using rapid link building as one of the weapons in the arsenal
