I probably shouldn't have jumped in on this thread since I don't know that much about DNA; sorry if it derailed the discussion.

But I will add that while my ethnicity results haven't helped me identify new ancestors, they have helped my genealogy research. Discovering I may have 1.4% Finnish ancestry has me looking differently at a couple of ancestors whose names never seemed to be spelled the same way twice and whose origins are mysterious. And the estimates of my percentage of Polynesian DNA closely match the number of Polynesian ancestors I had found through my paper-research, which was one bit of validation of that research and some oral history passed down through the family.