It sounds great on paper. AT&T (NYSE: T) -- the country's second-largest wireless carrier -- is on board with plans to roll out a family data plan soon. Verizon (NYSE: VZ) has been talking up family data for months, and a summer rollout seems likely.

Family data plans make perfect sense. Instead of shelling out for individual data plans, an entire family would be able to share a bucket of data.

Consumers would be naive to think that this will lead to smaller wireless bills every month. AT&T and Verizon aren't in this business to make less money, regardless of how they try to frame new offerings. Their goal is to have families embrace 4G tablets, hot spots, and netbooks -- ultimately slurping down more data (and naturally paying up for it).

Kicking the bucket
Obviously, you'll never hear carriers position their inevitable family data plans as money grabbers. AT&T, after all, is the same company that killed off unlimited data plans for new accounts by shifting to a stiff tiered pricing strategy two summers ago with the following headline:

"AT&T Announces New Lower-Priced Wireless Data Plans To Make Mobile Internet More Affordable To More People"

Ralph de la Vega, the head of AT&T's mobile business, told CNET and others attending a trade show earlier this week that family data plans are coming.

The structure of the plan is already in place, through de la Vega didn't provide any specifics. Has AT&T conquered the IT and billing issues that had it leery of going this route a few months ago? Will families have to pay fees for every device on the plan beyond the bucket of bandwidth that they're purchasing? Will "rollover minutes" apply to unused data as rollover data?

"We want to make sure we get it right," he said earlier this year -- but they probably won't.

How much for that iPhone in the window?
Family data will be a matter of feast or famine for Apple (Nasdaq: AAPL), hinging largely on how AT&T and Verizon plan to subsidize devices on shared data.

AT&T, Verizon, and Sprint Nextel (NYSE: S) are currently paying roughly two-thirds of the cost of iPhones that they're handing over to their customers. Can they continue to pay Apple an average of more than $600 per iPhone that they sell to their clients for as little as $199?

The size of carrier subsidies has been a bone of contention lately. The price consumers pay for iPhones in Spain more than tripled recently as carriers backed off subsidization tethered to long-term contracts. If family data plans grow popular, stateside wireless companies may have to rethink the math of subsidization.

Google's (Nasdaq: GOOG) Android devices -- which typically are more lucrative to both retailers and carriers -- will have more wiggle room in a climate that finds carriers slashing subsidies for smartphone purchases.

On the other hand, if the carriers sidestep what's going on in Spain and continue to shell out chunky subsidies, Apple is going to make a killing. After all, a bucket of data will make it that much more compelling for iPhone owners to pay an extra $130 for a 4G iPad. Carriers aren't subsidizing those anyway.

The fee police
The catch -- of course -- is that AT&T and Verizon may very well decide to slap a monthly fee on every single device feasting on the bucket of data. Nothing kills a buffet like a fee per plate.

The saving grace is that AT&T and Verizon -- and hopefully Sprint and the now-confirmed bachelor T-Mobile -- will ultimately have to compete against one another for business. They can't get too greedy, though we saw how AT&T and Verizon were able to orchestrate an end to offering unlimited data plans when their network capacities started buckling under pressure.

Wait a minute. Can AT&T's network handle the increase in bandwidth that family data plans may encourage?

I guess that's yet another question without an answer.

Opportunity's calling
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