Verizon (NYSE: VZ) is setting the ultimate trap to catch data hogs.

When Apple (Nasdaq: AAPL) hits the market later this year with its iPhone 5 -- the tech giant's first smartphone to play nice with Verizon's 4G LTE network -- the unlimited-data buffet is going away.

"A lot of our 3G base is on unlimited," Verizon Communications CFO Fran Shammo said this week at the JPMorgan Technology, Media, and Telecom conference. "When they migrate off 3G they will have to go to data share. That is beneficial to us."

Wait. Didn't Verizon join AT&T (NYSE: T) in nixing unlimited data plans last summer? It sure did, but that was for new customers. Existing Verizon customers were grandfathered in and allowed to keep the old unlimited bandwidth offerings, even if they upgraded their phones. As long as they remained active Verizon accounts, subscribers could avoid the tiered pricing plans.

Well, that's about to change.

Share and share alike
Verizon and AT&T have gone public with their plans to move toward shared data. They'd prefer to sell customers a bucket of data and let subscribers share it with other mobile devices. A family data plan, for example, would offer tiered pricing for a large pool of bandwidth that could be shared among smartphones, tablets, netbooks, and mobile hotspots.

Both companies have been dropping hints about the shared family data plans that they plan to roll out later this year, but Shammo's admission this week is the first time any executive has told customers their days of unlimited data are, in fact, limited.

On the surface, this doesn't sound like a bad idea. Most mobile customers on tiered pricing plans have plenty of bandwidth that expires unconsumed at the end of their billing cycles, so why not share it?

But let's not mistake this as a way to save money on wireless bills by bundling services. Shammo specifically said the shift will be beneficial to Verizon, and that means accounts on average will be paying more.

That alone is going to scare some customers.

The pause that refreshes
Verizon is this country's largest wireless carrier, and AT&T is a close second. What do you think will happen when Apple introduces its 4G LTE iPhone either this summer or early in the fall? Verizon customers who typically jump on eligible upgrades may think twice about migrating to the iPhone 5 if they don't want to kiss their unlimited data plans goodbye.

That would actually help Verizon -- and AT&T, if it follows suit -- by milking more months, if not years, out of the big iPhone subsidies paid to Apple whenever someone buys a new iPhone or goes for an upgrade.

Apple, on the other hand, won't be sitting pretty if Verizon and AT&T customers are slow to embrace the iPhone 5. Making the logical leap to Sprint Nextel (NYSE: S) -- the last of the three major domestic carriers still offering unlimited data plans to new customers -- may not be feasible for some, given the iffy perceptions of Sprint's high-speed network.

The upside of change
This doesn't have to end badly for Apple. The world's most valuable tech company may sell more of its 4G iPads, as Verizon customers who have resisted taking on a new data plan buy into the shared data. There will also be a push for mobile-gadgetry makers to make more of their products compatible with carrier networks, opening up new categories of Web-enabled devices beyond Wi-Fi.

However, this will also open new opportunities for Apple rival Microsoft (Nasdaq: MSFT). The arrival of shared data comes at a time when Mr. Softy is gambling on its tablet-centric Windows 8 operating system upgrade and the fleet of Windows tablets and ultrabooks that will follow.

There doesn't have to be one single winner, of course. The only loser that we can be sure of is your pocketbook.

Apple jacks
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