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Apple's iOS 9 may have hurt publishers and carriers with its inclusion of ad-blocking apps. Source: Apple

There's been a huge shift in how Americans pay for their smartphone network over the last decade. Earlier billing schemes that centered on talk minutes and number of texts for monetization gave way to mobile data after Apple's iPhone popularized mobile browsing. Talk and texts are now essentially treated as loss leaders amid data-based pricing.

And that makes sense for carriers, as data usage has exploded. According to Cisco, the average North American mobile user used 1.3 GB of mobile data per month in 2013, doubling from 752 MB in the prior year. And according to Cisco's data, this number is only going to increase, as the router maker estimates the average user will use nearly 9 GB per month.

However, a recent report from The New York Times shows that much of that billable data is spent not on reading desired content, but actually on undesired advertisements. So, unfortunately, web ads aren't just irritating -- if you browse them through your mobile network, they're also costly. Of course, with the rise of ad-blocking software on Apple's iOS, carriers may lose revenue as ad-based data usage decreases.

Half of your data is spend on content you don't want to see
According to The Times, more than half of data used browsing the mobile versions of the top 50 news sites were spent on ads. Assuming you're not insane, this isn't the content you wanted to see. Even worse, if using the network -- and not WiFi -- you are paying for this content. And it seems all sites aren't equal in this regard.

Per the study, Boston Globe's video-heavy website is by far the largest offender. In terms of time to load ad-based content, Boston.com takes 30.8 seconds to deliver ads -- almost four times the time it takes to load the editorial content users came to the site for (8.1 seconds). As a comparison, the second-worst offender, conservative website The Blaze, takes nearly 12 seconds to load ad content, versus 7 seconds for editorial content. You may have noticed many websites have turned to somewhat desperate measures to convince readers not to use ad-blockers.

The largest carriers are the worst for data plans
If you are a subscriber of the third or fourth largest U.S. mobile carrier -- T-Mobile (NASDAQ:TMUS) and Sprint (NYSE:S), respectively -- this really isn't a large issue, as those carriers have unlimited-data contracts. For example, T-Mobile's individual unlimited talk, text, and unlimited smartphone data plan is now $80 monthly. Sprint is actually cheaper, as the company now advertises an unlimited high-speed data, talk, and text for $60 per month.

However, if you are one of the collective 259 million Verizon (NYSE:VZ) or AT&T (NYSE:T) subscribers, it's unlikely you have an unlimited option for data.

Unless you're grandfathered into an unlimited-data plan, these two carriers charge for data by the gigabyte, and Verizon is actually looking at raising the price on those covered on its unlimited-data plans by 67%. Both companies have a history of attempting to limit unlimited-data customers with their controversial network management policies, which initially appeared to be unrelated to actual network performance.

For these two carriers, those pesky ads you have to sit through in order to read the editorial content you went to the site for are more than simply a nuisance -- they're actually costing you when you are on the carriers' networks. My assumption is mobile-ad blockers will become more common and hurt publishers, with carriers getting hit in the process.

Jamal Carnette owns shares of Apple, AT&T, and Sprint, and is probably included in one of the ones that will get hurt by the rise of ad-blockers. The Motley Fool owns shares of and recommends Apple. The Motley Fool recommends Cisco Systems and Verizon Communications. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.