Shared plans have been available in the US and Europe since 2012. Surprisingly, carriers have seen consumers spend more on mobile data as a result, not less. Consumers tend to spend more because they buy bigger data plans and add more devices to the account. Family plans are popular and encourage everyone to use the same carrier. Telstra has already released a mobile shared service for business customers charging a basic fee of $60 per month for 1.1 gigabytes (GB) of data, plus a $10 sharing fee and $10 per device. Up to 8 GB can be bought for an extra $60 a month. "We will be launching data share plans for [post-paid] consumer customers in the coming months, allowing them to share data across a number of mobile devices [such as smartphones, tablets or mobile Wi-Fi]. The plans will suit people who want to streamline and make the most of the data they pay for without any complications," a Telstra spokesman said, without giving a launch date. An Optus spokeswoman said it was looking at data sharing, but wanted to address bill shock and international roaming first. A Vodafone spokeswoman said it considers pricing options regularly. But neither committed to a date.

In the US, AT&T and Verizon offer data, voice and message sharing on up to 10 devices. These carriers charge a fee for data and for each device. For example, a basic shared plan on Verizon costs $US40 per smartphone, $US10 per tablet and $US70 for 4 GB of data. Senior mobile analyst at Ovum, Nicole McCormick, said she expects to see more than one Australian carrier offering this new pricing structure by the end of the year. "Consumers do benefit from these plans since it is cheaper to have a unified account. However, this results in subscription revenue loss for the telco in the case that a person consolidates their multiple accounts [eg dongle, tablet and smartphone] with that telco. Ultimately, these plans are part of the operator's anti-churn management strategy, since a subscriber – either a connected person or connected household – is less likely to churn on a shared plan." Goldman Sachs telecommunications analyst Raymond Tong recently released a report showing monthly spending in the US increased by about $US10 a month after shared plans were introduced and that the number of devices using networks increased substantially. "Strong take-up of shared data plans has encouraged incremental take-up of additional connected devices [eg tablets] and greater data usage. This has resulted in strong growth in average revenue per account. Demand has been strong since Verizon and AT&T launched these plans in mid-2012, with 36 per cent of wireless accounts at Verizon already on these plans," Mr Tong wrote in a note to clients.

Sharing has become possible thanks to new billing technology, according to Alcatel-Lucent's vice president for payments, policy and charging, Fran Heeran. Consumers tend to ease back on data usage when they get close to a monthly cap, rather than fork out for additional data, Heeran said. "When carriers add it all up, they see people use more data and buy more data in a shared plan than in individual plans." The real-time billing allows families to control how much data each device gets to use and when, allowing parents to turn internet access off during certain hours or limit their children's data usage. Alcatel-Lucent has also found app-specific billing options were quite popular overseas. Consumers could stream unlimited video through a service, such as iView or Foxtel, for a small additional fee every month, or buy speed boosts to make particular apps run faster.

How much you can save A small business that supplies phones to four employees could save $100 per month using data sharing. Four phones would cost $100 per month on Telstra's shared plans for businesses, compared to $200 for four phones on individual plans. The difference is all four phones would share 1 GB of data every month, rather than having 1 GB per phone. Increasing to 3 GB of shared data would cost an extra $30 per month, still $70 cheaper than individual plans. However, data sharing on two phones and two broadband dongles is not necessarily cheaper. The maximum of 8 GB data sharing would only be about $10 cheaper and have less data than two individual phone and two individual dongle plans. This would cost $150 per month for the four devices with 1 GB per device. Increasing to 4 GB per device would cost a total of $170 per month. Sharing would cost $100 per month with 1 GB of shared data, and increasing this to 3 GB or 8 GB would cost an extra $30 and $60 respectively. So the option is $160 for a total of 8 GB or $170 for a total of 10 GB.

Australian reseller Dodo already offers data sharing on up to five devices. It charges $5 per month for each additional SIM card, plus a $20 activation fee per SIM. So sharing 4GB among five devices would cost a new customer $65 per month plus $80 set-up fee.