The third provenance challenge was organized to evaluate the efficacy of the Open Provenance Model (OPM) in representing and sharing provenance with the goal of improving the specification. A data loading scientific workflow that ingests data files into a relational database for the Pan-STARRS sky survey project was selected as a candidate for collecting provenance. Challenge participants record provenance, run queries over it, and export/import provenance as OPM documents with other teams to verify interoperability. Fourteen teams participated in the challenge that concluded at a workshop in June 2009 in Amsterdam. The experiences of several participating teams are included in this special issue. In this editorial, we describe the challenge in detail, review its outcome, and introduce articles included in this special issue.