They do have/had a partnership - familysearch and ancestry
http://corporate.ancestry.com/press/press-releases/view/?id=299
http://www.familysearch.org/eng/home/news/frameset_news.asp?PAGE=Press/2008-7-21_Enhanced_US_Censuses.asp
http://ancestryinsider.blogspot.com/2011/07/familysearch-embracing-world.html