The Generations Network, parent company of Ancestry.com, has been granted a U.S. patent for a "method of consolidating genealogy records [that] includes partitioning the records using at least one index file to form one or more partitions, sorting the records in a partition based on a data element in the records, comparing records within a sort range, based on the comparison, identifying same person records, consolidating information in the same person records, receiving a request from a user to view at least a portion of the consolidated information for a particular group of same person records, and sending a file that includes the portion to the user."
That is a mouthful, but I think it means that the software finds probable matches in a huge database in order to find the same person in more than one entry.
Assigned to The Generations Network Inc., Provo, the patent was granted to Bennett Cookson Jr., Kendall J. Jefferson, Grant Parkinson, Douglas T. Reid, Daren Thayne, all of Orem; Ken Boyer, Cedar Hills; Jerry Collings, American Fork; James Mark Hamilton, Provo; Michael J. Wolfgramm, Pleasant Grove..
The patent was filed on December 29, 2003, and only granted recently, on July 24, 2007. You can find full details of patent number 7,249,129 at http://www.freepatentsonline.com/7249129.html.