Another example of the potential of mobile commerce comes from Pizza Hut, with its iPhone app generating $1m in sales in the three months since launch.
The app, which allows customers to order food on the move, is approaching the figure of 1m downloads. It is only available in the US at the moment.
The app's success so far has undoubtedly been helped by it featuring in Apple's ads in the US, but it also shows that there is an opportunity for similar food brands to profit from launching iPhone apps and mobile sites.
As surveys have suggested, items and services that people need while on the move, such as food, movie tickets and hotel rooms, have appeal for mobile users.
In the US, Burger King has been trialling an app that allows users to order ahead, pay for items on the phone and skip queues, and others may well follow suit when they see the potential of mobile apps.
In the case of Pizza Hut, it makes sense to allow customers to order food any way they want and, according to Pizza Hut, the app is driving incremental sales.
Along with eBay's iPhone app, which has had more than more than 4m downloads so far, the Pizza Hut app shows how retailers can make the most of mobile to drive extra sales, though there aren't too many examples in the UK so far.
Indeed, thetrainline may be missing a trick by not adding the option to book tickets through its iPhone app, and gain a valuable headstart in this market.