If AT&T customers want to keep tabs on their data usage, they can track usage on att.com/dataplan or dial #DATA# to get a text message updates. The company also says it sends customers three messages a month warning them as they approach the monthly data usage limit.
Regardless of the legal outcome, industry watchers say the suit spotlights the need for more customer awareness around the data technology powering their phones.
"A lot of people think they're only using data when they're using the Web, [but] in fact many apps are essentially cloud-based apps that use significant amounts of data," said Greg Harper, president of technology consulting company Harpervision. "People are buying smartphones and don't realize that what makes them smart is the data. ...The real problem is better visibility of the data usage."
AT&T's data billing practices have been an ongoing source of customer complaints, Harper said, but added that much of the problem may lie in consumer confusion.
"So many of these programs are just a storefront end to cloud data," he said.
While the application icons may live on your smartphone screen, the processes that actually calculate distances on a navigation app or translate foreign phrases with Google Translate take place on other computer servers, in the so-called "cloud." The customer gets charged as the data moves in and out of the phone.
Even if customers don't use all of the applications on their screens, many can soak up data with ongoing updates, he said.
Lance Ulanoff, editor-in-chief for PCMag.com, said tracking data consumption can be confusing for consumers, but basic actions, like disabling location services and turning off WiFi, 3G or GPS functions when they're not necessary, can help.
When it comes to calculating data usage, he said, "It's more art than science."
Data consumption turns on a range of factors, such as whether an application is location-aware, whether a web page is optimized for a mobile device or whether you're streaming music or video, he said.
"I definitely think that the educated consumer is one who is best armed to talk about and understand how much data they're using and how much they should be charged for it," he said.