Geni.com

Geni is solving the puzzle of genealogy by inviting the world to build the definitive online family tree. Users add and invite their relatives to join their family tree, which Geni compares to other trees. Matching trees can be merged into Geni's World Family Tree, which currently contains over 145 million people.  Geni welcomes casual genealogists and experts who wish to discover new relatives and stay in touch with family.