Family Tree Maker for Macintosh. At that time, the company said "before the end of the year." (See http://blog.eogn.com/eastmans_online_genealogy/2010/04/ancestrycom-announces-new-macintosh-version-of-family-tree-maker.html for details.) Now the Ancestry.com blog says, "The Mac version is on schedule to be released within the next two months."
The one-line statement may be found at http://blogs.ancestry.com/ancestry/2010/09/14/family-tree-maker-more-about-2011/ but details are not provided.