thread made me smile, as an historican speaking: without a genealogical tree in an old familybook (possible chance of counterfeit) or even better an offical issued proof of ancestry chances are high that your ancestor were Joe and Jane average, nothing more...
If you had some famous ancestors or want to find out about it, you can try to contact an institut for genealogy at an university or go to a church archive to study old church registers (where you are probably screwed if you cant read latin), if by some chance you're a descendant of an important noble lineage, your family should have its own archive...
don't let you fool you: the ancestry stuff on the internet is nothing more than viral marketing and there are always tall-tales in the oral tradition of your family history. If it can't be proofed by scientific standards, it's worth nothing.