Verizon has quietly begun throttling the wireless connections of its heaviest data users, the company revealed in a PDF buried on its website (hat tip to BGR). The document explains that Verizon has begun two new network management practices in order to "provide the best experience to our more than 94 million customers," and that they go into effect starting today, February 3.

In the document, Verizon says it's using techniques such as caching less data on its network, reducing network capacity, and sizing video "more appropriately" for devices. "While we invest much effort to avoid changing text, image, and video files in the compression process and while any change to the file is likely to be indiscernible, the optimization process may minimally impact the appearance of the file as displayed on your device," Verizon writes.

The company also insists that the process is content-agnostic—likely to avoid the outrage that came when Comcast began throttling Bit Torrent users. Verizon's PDF points to www.verizonwireless.com/vzwoptimization for a more detailed explanation of its optimization "techniques," but as of this writing, that page remains unavailable on Verizon's site.

Along with video compression, Verizon is now reducing data throughput speeds for customers that fall into the five percent of customers who "use an extraordinary amount of data." The throttling could last through the remainder of the current billing cycle and the next one, so those who find their data speeds being held back may end up suffering the consequences for months afterwards.

"Our proactive management of the Verizon Wireless network is designed to ensure that the remaining 95 percent of data customers aren't negatively affected by the inordinate data consumption of just a few users," the company wrote.

The timing for Verizon's new throttling policies is no coincidence; today is also the day the carrier began accepting preorders for the long-awaited Verizon iPhone 4. Verizon will undoubtedly begin to feel the weight of iPhone users' browsing habits when the device becomes available to customers on February 10, just as AT&T did when the iPhone first launched on its network in 2007.

It took AT&T years of building out its network to better handle the load, and Verizon knows that it needs to balance things out from the beginning. After all, a study from last July showed that Verizon 3G users gobbled about 25 percent more data than iPhone users did—now that Verizon's about to have its old customers and new iPhone users snarfing down data like no tomorrow, network management has apparently become a bigger priority.

Another point of note is Verizon's position on the latest net neutrality rules. The company sued the Federal Communications Commission last month to block the rules from taking effect, even though they are comparatively light on wireless communications. Still, with the decision to throttle heavy data users, Verizon is obeying what's outlined in the FCC rules by making sure the implementation is site- and content-agnostic, as well as by being transparent about its practices. The company knows that the move isn't likely to be popular, so it's trying to offer as much information as it can so that users can understand better what's going on behind the scenes.