One pillar of the success of Stefansson's strategy has been his ability to convince tens of thousands of people to volunteer to take part in deCODE's research, and to connect and analyze their data using the genealogies. An early partnership with local software developer Friðrik Skúlason created a computerized national genealogy database that linked all living Icelanders and included the majority of people who have ever lived in Iceland over the past eleven hundred years. In 2003, one version of this database, called Íslendingabók, was made freely available online to anyone with an Icelandic national identity number, and is used by thousands of citizens every day. The version used in research replaces names with encrypted personal identifiers overseen by Iceland's Data Protection Commission. This makes it possible to create pedigrees connecting the genetic and phenotypic data of any group of people in an anonymized manner. Stefansson and Gulcher published the structure of this data protection system for other genome projects to use.