I had this discussion with a friend of mine from work the other day who is European Jewish from Poland, and he pointed out to me that he wouldn't expect much of a match because of the holocaust. He feels that most of his family and even distant cousins were wiped out completely. His parents weren't married before the war and are both concentration camp survivors.
I told him he should do it anyway at least to find possible survivors of his extended family and to get his results cataloged for future generations.