Internet advertising reached an all-time high last year, around $50 billion, and a good amount of that actually went towards programmatic ad revenue – even at a time when companies are still trying to get a better understanding of how it works.

AdAge recently reported that programmatic ad revenue makes up over one-fifth of overall Internet advertising, with a total of $10.1 billion for 2014. This comes from a survey conducted by PricewaterhouseCoopers, on behalf of the Interactive Advertising Bureau. That makes up for nearly half of all revenue from online display advertising, a whopping number when you consider that some companies are putting up with inconsistencies from it.

Some companies define programmatic in different ways, while also dealing with pratfalls in ad formats and media marketplaces, according to the research. Programmatic seems to refer to display and video ads on desktop and mobile that were bought and sold through automated channels – a practice some companies are still getting used to.

“I wasn’t surprised by the findings so much as the challenge it took to get clean numbers,” said Sherrill Mane, senior vice president of research, analytics and measurement for the IAB. The company went to great lengths to avoid double-counting revenue, according to her. “We need more consistency and clarity around what we’re talking about, and the value of automation and targeting and efficiency will come through.”

According to the report, only ten companies account for 66 percent of the $10.1 billion programmatic revenue, with 25 percent accounting for 75 percent overall. A lot of these industry leaders make money through programmatic buying and selling before the revenue even makes its way to publishers, including a variety of technology companies that facilitate sales for publishers and buys for marketers.

With the charge-up for fees regarding these platforms or ad servers, tech companies can charge a markup from 15 to 50 percent for the cost of the ad space. One example of this includes ad networks, facilitating the purchase and sale of online ad inventory, typically charging 30 to 50 percent in value-add mark-up fees, with certain networks possibly charging even more, according to the report. The IAB also noted that, by contrast, feels for demand-side platforms, agency trading desks and exchange marketplaces can fall below 30 percent.

Meanwhile, display banner ads for desktop and mobile devices made up a good portion of programmatic revenue, 80 percent per the report. Although these ads are popular, there are still challenges when it comes to tracking and targeting audiences across devices. The study notes, “For example, behavioral data available in apps may not be available outside of those apps,” making it hard to track overall engagement across both desktop and mobile devices to see which is more effective.

So where exactly is programmatic bought and sold The report notes that open auction marketplaces make up 70 percent of programmatic revenue for the past year, while invitation-only auctions and automated- guaranteed markets make up the other 30.

But there are still questions being raised about buying and selling in the programmatic market. “In its current state, the open auction market is perceived as a big black box for advertisers, and demand from advertisers for greater control over brand safety, ad verification and performance measurement will require better solutions,” said the report.

ROI also remains difficult to calculate overall, and ad fraud and server ads continue to be a problem when it comes to viewable inventory. “With our estimate of approximately 45 percent of programmatic revenues reaching publishers, understanding where dollars are distributed across the ad-stack from advertiser to publisher can be quite disorienting in the current programmatic landscape,” says the report. “Are the added costs of programmatic buying and selling resulting in stronger overall revenues than traditional direct sales ”

More information on the report can be found here.