When you have multiple people in your family or multiple devices, having separate full cell phone contracts can be expensive--prohibitively so.
Carriers long ago recognized this and came up with voice plans where you purchased a pool of minutes and shared them among family members. When texting became popular, similar pooled text message plans became options at some carriers. Billing has not kept up with technology though. Now that data plans are popular, and have been for several years, we still have no way to share data pools with family members or multiple personal devices. AT&T at least acknowledged that shared data plans are under consideration.
It is unclear exactly what AT&T CEO meant when he said, "But once you have so many devices that you carry, you may want a shared plan. The more focus groups we do, the more we think that may be the way. We're working on it. It will be soon." It may be similar to voice and SMS plans where anyone on the family plan gets to pull from the common pool of resources.
It may be geared, however, towards people with one voice device and multiple data devices. People typically have one personal phone, but they may have a tablet, MiFi, netbook, data dongle, or other data device. Some people though, mobile device geeks in particular, may have multiple phones. With GSM carriers like AT&T, it is real easy to swap out the SIM card to quickly change the phone you are using, but that can be a pain if you want to get email on one device and play an online game with another. A lot of rebooting happens when swapping out SIM cards. If AT&T allows people to use several different phone devices, that process becomes much easier. The next logical step then is to allow a family to pull from a common data pool.
We'll have to wait and see what AT&T's intentions are and what the pricing would be. With voice plans, carriers typically charge $10 for each additional device that pulls from the pool. This news may also spur other carriers to follow with their own share data plans.