I have 2 site ranked 22 and 23 for my keyword. Both site were created the same day, have zero backlinks and are optmised the same way. They are both blogs with different content. but same KW density. both have the domain mykeyword.org and mykeyword.net. I will send 1000 directory submission to mykeyword.org and report back in this thread in a couple of weeks to see the difference in rankings.