AT&T today announced its own version of shared data plans. The plans provide consumers with a fair amount of flexibility when it comes to matching a service plan to their individual needs. Like Verizon's shared data plans announced earlier this year, AT&T's plans bundle together voice, text, and data and allow multiple devices to share from the same pool.

The idea has merits for consumers, especially families. For example, before today, a family of four, each with his/her own smartphone, could share voice minutes, but each device had to have its own data plan -- adding significantly to the overall monthly cost of the plan. Throw in a tablet for the kids and a mobile hotspot for mom or dad, and monthly data costs can spiral upwards at a dizzying rate.

Worse, one device on the plan might use more than its monthly allotment of data, while others use only a fraction. It's hard to swallow a data overage fee at the end of the month on one device when a different device on the same account used less than half its monthly data allotment. (In fact, I'm pretty sure I'd be hopping mad about it.)

[ How do you engineer a successful mobile device management plan for the enterprise? See 6 Keys To A Flexible MDM Strategy. ]

Shared data plans from AT&T and Verizon Wireless are meant to help tackle this problem. Instead of charging each device for its own mobile data allotment, the shared plans provide larger buckets from which all the devices draw. For example, AT&T is offering monthly data buckets ranging from 1GB to 20GB, with basic access fees ranging from $40 to $200. Allowing devices such as smartphones, feature phones, laptops, tablets, hotspots, and netbooks to pull from this same bucket means it'll be easier for groups to balance data usage.

However, the idea appears to work best for a family or other small group. Consumers--and probably very small businesses--could very well save money on a monthly basis with the shared data plans. But AT&T's Mobile Share plan maxes out at 10 devices per account. That makes it unusable for most businesses.

Large enterprises--especially ones that distribute devices directly to employees--should not approach mobile services this way. Instead, they should be speaking to the enterprise sales teams at AT&T, Sprint, T-Mobile, Verizon Wireless, et al., about getting customized rates. When your business is purchasing hundreds or thousands of devices, it has a bit more wiggle room with the carriers when it comes to negotiating rates for voice minutes, messaging, and mobile broadband.

One scenario in which a shared data plan might make sense is large enterprises that use the Bring Your Own Device (BYOD) model. If Employee X has a smartphone, tablet, and laptop, the enterprise could provide that employee a shared data plan that covers all his/her devices rather than sticking him/her on an account that covers multiple employees.

As with most services, consumers, small businesses, and large enterprises will get different mileage from shared data plans depending on their individual circumstances and needs. While consumers and small businesses might have a bit less pull when it comes to customizing their services, big businesses should be engaging wireless network operators more directly to get the best possible rates.

At this year's InformationWeek 500 Conference C-level execs will gather to discuss how they're rewriting the old IT rulebook and accelerating business execution. At the St. Regis Monarch Beach, Dana Point, Calif., Sept. 9-11.