AT&T today said it will restructure its pricing plans for data, lowering prices but killing all-you-can-eat options for the iPhone and other smartphones. Similar moves are surely in the offing for both Verizon Wireless and T-Mobile USA, each of which has recently spoken of the need to ditch traditional plans in favor of usage-based models; Sprint is likely to fall in line eventually. But just how drastically these new pricing models will affect the consumption of mobile applications — a space that is beginning to soar – is unclear.

While AT&T will surely draw plenty of arrows for being the first carrier to end unlimited offerings — it’s already getting an earful from rightfully irate owners of the iPad 3G — the need for new pricing models is as obvious as it is urgent. Data traffic is ramping up at a breakneck clip, outpacing voice traffic for the first time in December 2009. And there’s no end in sight thanks to the surge in smartphone sales, which inevitably leads to increasingly taxed networks. (Feel free to ask AT&T if you don’t believe it.)

Low Caps and Brutal Penalties

As Stacey writes today on GigaOM, parts of AT&T’s new plans are “downright punitive.” Users can choose between a low-end plan for $15 a month or spend $25 to get 2 GB a month. And AT&T puts the hammer on people who exceed those limits: Those who blow past the low-end cap must essentially double their plan for the month, buying an additional 200 MB for $15 more dollars. And high-end users who exceed their allotment of 2GB pay $10 for each additional GB they use. But  the punishment isn’t just being meted out to heavy data users; the makers of applications that deliver the high-bandwidth goods should be sweating the changes to AT&T’s pricing plans as well.

AT&T rolled out a few tools to help customers keep tabs on their usage including a text-alert service that informs customers when they reach 65 percent, 90 percent and 100 percent of their monthly allotment. A more illustrative tool, though, is AT&T’s data calculator, which enables subscribers to approximate their usage to find out roughly how much data they use in a month: Watching a half-hour of video every day and listening 300 minutes of music a month (which seems extremely conservative for fans of streaming services like Pandora) results in an estimated monthly usage of 1.86 GB — and that’s before you account for more mainstream offerings like e-mail, picture messaging, game downloads and the mobile web.

It stands to reason, therefore, that caps will prevent many subscribers from downloading and using as many apps as they do now. That’s bad news for rich-media app makers like Pandora, which found some much-needed success thanks to its popular mobile app. Or what about the impact on  publishers betting the farm on apps for the iPad, which can support more immersive (and data-intensive) content thanks to the performance and sheer real estate of its great touchscreen? The caps seem even more conservative when you consider iAd, Apple’s new ad network that promises to deliver campaigns in rich media on the iPhone, iPad and iPod touch. Those campaigns may be engaging, but they are sure to draw the wrath of some consumers who realize they’re paying a pretty penny to watch mobile commercials.

Bandwidth: A Scarce Resource

But as Mark Collins, AT&T’s senior VP of data and voice products, mobility and consumer products, told Stacey today, mobile bandwidth is now a scare resource, and “you need to price it according to the value equation so the market can allocate the resources accordingly.” While AT&T decided that metered pricing is the best solution, there are other ways for operators to exact higher fees from those 3 percent of users who account for 40 percent of the traffic on the network, without infuriating the remaining 97 percent and also continue to encourage users to download and use mobile apps? That’s a question many app developers are asking themselves as they wait to see how carriers address the market.

Among the other pricing models that may emerge as carriers struggle to monetize mobile data and ease congestion are Quality of Service (QoS) options that charge steep premiums for superior speeds and unlimited performance, then offer less-expensive tiers at a variety of price points and service levels. We may also see congestion pricing, which imposes additional charges for traffic at peak hours and cuts deals for those consuming data at off hours. Another option would allow consumers to work with service providers to create customized service offerings. And network operators are wisely warming to offloading technologies such as Wi-Fi that enable users to access unlimited amounts of data without weighing down the network.

A Speed Bump for Data Consumption?

Regardless of what strategies carriers employ, though, there’s no question that some applications will be impacted as the era of unlimited comes to an end. Streaming video providers – like ABC, which offers a great app for the iPhone – are likely to be targeted by network operators who currently deliver the data-heavy content but don’t enjoy proportionate revenues. And services such as Pandora, which streams music to users based on their listening preferences, may see waning demand from AT&T subscribers.

“I am still surprised that certain operators and apps assume that unicast video over a limited capacity/spectrum wireless network should be ‘normal and accepted,’” Accel Partners’ Richard Wong told me via e-mail a few weeks ago. “No way – it’s as if one is driving in four lanes of the highway at once and hogging it all. I do think one has to care about the data pollution and footprint, and not assume all bandwidth is free as an app.” And Wong cited the emergence of new technologies and software that help carriers support increased traffic on existing networks.

Opportunities in Technology — and Elsewhere

Those new technologies include everything from LTE networks, which offer lower data delivery costs for operators, to compression offerings from companies like Sonoa Mobile that enable developers to lighten the data impact of both downloading and using an app. The increasing need for those kinds of solutions provides new opportunities for players in the value chain who can help developers and content companies lighten their loads. A streaming music provider that leverages superior compression technologies, for instance, could market itself as a player who delivers a better music experience at lesser bandwidth than the competition.

But it’s not just about the technology. GoldSpot Media, a Sunnyvale, Calif.-based startup, is hoping to differentiate itself from the vast number of players in the mobile advertising field by delivering ads overnight and at other times when network congestion is less of an issue. The video ads are stored on the handset and presented to users through mobile applications once the mini-commercials have been fully downloaded. Similar strategies could include delivering ads only when users are connected via Wi-Fi but not when they’re on the cellular network. Such strategies would hold immense appeal for developers looking to monetize their offerings while protecting their customers from onerous data charges.

Developers and publishers of some data-intensive apps may need to tweak their business models as carriers work out their new pricing models, but the market will also come up with solutions that help boost carriers’ bottom lines without punishing those behind the surging app phenomenon. “It’s true that something has to give at some point. The continuing consumptive nature of many mobile apps but the undeniable physics of spectrum/bandwidth and throughput means there is going to be a breaking point,” Wong wrote. “[But] this app wave isn’t slowing down anytime soon. I just think it will manage to these new realities…. I think we will overcome.”