Earlier this fall, the ad industry gathered in New York City for one of its biggest annual trade conferences. The topic on everyone’s mind: How do you fairly measure video views?

News that Facebook had long oversold a key metric in how it quantified video views had shocked marketers, and the social network had deployed some of its most prominent executives to do damage control.

But despite the mea culpas, there was a pervasive sense that a reckoning was only just beginning -- not just for Facebook, but for all enclosed online platforms that ask advertisers to accept their proprietary numbers on the strength of their word alone.

"[It's] probably just the tip of the iceberg," Bill Bruno, CEO of the marketing analytics firm Ebiquity, said at the time, predicting the debacle would lead advertisers to demand more transparency from these networks.

Weeks later, Facebook is now admitting the problem was far more widespread than a single measurement error. A full-scale internal audit of its analytics systems revealed several more bugs and miscalculations across the company's various standards -- granted there are hundreds of them -- for how users interact with ad-related content.

Steps in the right direction

While advertisers are encouraged by how forthcoming Facebook has been, many believe the company's metrics desperately need further third-party supervision.

"It's like having the ability to grade your own homework," Bob Liodice, CEO of the Association of National Advertisers, told Mashable.

"We do applaud Facebook for acknowledging the need for greater degrees of transparency," he continued, "but we also want to continue to encourage Facebook to pursue all of the third-party verification opportunities possible."

GroupM, the ad-buying arm of holding company giant WPP, echoed the trade group's concerns in its own statement.

"We’re encouraged Facebook is clarifying metrics and seeking input from customers," a spokesperson said. "Today’s developments stop short of full third-party measurement which we still believe crucial to advertiser confidence in any market."

Facebook too recognizes this reality. The company took some preliminary steps towards such a system with Wednesday's announcement, in which it laid out plans to convene an independent council that will preside over measurement matters. The company already partners with analytics firms like Nielson and Comscore on a limited basis.

But the ultimate goal, Liodice says, is to bring Facebook's metric system under the auspices of the Media Ratings Council, an esoteric yet hugely influential independent agency that has set measurement standards in the industry for decades.

Facebook has indicated in ongoing conversations with each of these groups that it is amenable to that arrangement, he says.

"Right now, our view is that third-party verification is the most important thing," says Carolyn Everson, Facebook's VP of global market solutions. "[Clients] want to know that [data is] verified and that they should trust and have confidence in it."

Jason Kint, CEO of publisher trade group Digital Content Next, put the conundrum in blunter terms when asked about an error Facebook made in measuring traffic to its fast-loading Instant Articles.

"[It's like a] fox guarding the hen house," Kint said in a private Twitter message. "It never ends, and it never works."

Broken trust?

While Facebook's open communication in this case is admirable, the fact that it's been operating under faulty pretenses for so long does raise questions about how much faith advertisers should place in metrics going forward.

"There are those concerns -- especially when folks are asking, 'What do we get in return for our campaigns?'" says Jake Schneider, director of digital strategy at Austin-based agency The Marketing Arm. "To their credit, [Facebook is] opening up and being completely transparent and saying, 'We messed up.'"

While Facebook still has a ways to go to reach the level of accountability advertisers would like to see from it, the company has the chance to lead the way for other platforms if it does fulfill the steps it's laid out for itself.

"The fact that they're embracing what advertisers want -- the fact that they're bringing in these third parties -- I think that's good for the industry," said Scott Knoll, CEO of metrics firm Integral Ad Science, which has worked with Facebook on viewability issues. "You have to remember that two years ago, nobody was requiring third party on anything so we've come a long way."

Not everyone agrees. One leading ad industry figure who declined to be named for the sake of preserving business relationships said the entire digital media supply chain is broken and needs a hard reboot.

This person compares the ad assembly line to a "Rube Goldberg machine" in which intermediaries don't necessarily act in the best interests of the advertisers ultimately footing the bill. Opaque proprietary metrics keep the imbalance between different parties in the dark.

Facebook, for its part, seems to at least be indicating that it's ready to lower the barriers of its walled garden in this respect and give advertisers more of a window into the process.

"What I would tell you is we are not going to be perfect," Everson said. "What we are going to strive to be is as accurate as possible and fully committed to being transparent if we find things and certainly as we update our metrics."

Duopoly dilemma

While some marketers may be frustrated with Facebook's lack of accountability, don't expect to see many fleeing the platform entirely.

For one thing, the company's ad business is still growing at a rapid clip, and it offers a value proposition brands can't get anywhere else online.

But Facebook is also one of two dominant forces in the digital ads market -- along with Google -- leaving advertisers few other options for the kind of massive online reach it offers.

That duopoly environment has the potential to pose problems should advertisers need to pressure either of these companies to meet their demands.

"An industry in which two companies capture all of the growth and measure themselves seems highly questionable," Kint said.

While Facebook might be content to move towards mutually beneficial goals at its own pace, the responsibility ultimately falls to the few biggest brand advertisers to hold its feet to the fire, Bruno says.

"It's going to have to be the ones with the budgets that cause the change," Bruno said. "It's going to have to be the bigger players asking the questions and putting the pressure on these walled garden systems to take a higher level of accountability."

Mashable's Kerry Flynn contributed to this report.