The meet-up resulted from an open letter sent by the IAB last month to comScore and Nielsen//NetRatings asking both firms to consider external audits.
Exactly what issues were discussed, and whether any agreements were reached remains to be seen, as the parties involved are not talking.
"We're maintaining a veil of secrecy for now," said Randall Rothenberg, president and CEO of the IAB. Rothenberg did say "the meeting went very well."
All will be revealed next week, according to Marla Nitke, IAB's director of marketing communications. "We'll have some significant things to share," she said.
On April 20, Rothenberg issued a public letter explaining: "All measurement companies that report audience metrics have a material impact on interactive marketing and decision-making. Therefore, transparency into these methodologies is critical to maintaining advertisers' confidence in interactive--particularly now, as marketers allocate more budget to the platform."
"Tensions are running high as the Internet becomes the center of all marketing," Rothenberg told OnlineMediaDaily at that time, spelling out the gravity of the IAB's request.
Both comScore and Nielsen issued initial public responses soon after the IAB's request for third-party audits.
Nielsen//NetRatings said it was in the process of securing third-party certification of its methodologies, and that it had already completed the Media Rating Council's pre-audit.
comScore said it had recently opened its methodology to an evaluation by the Advertising Research Foundation, and that it planned to release the results publicly in the near future.