Another technological development was the introduction of tablet computers. These handheld devices are larger than a smart phone but smaller than a laptop computer. Most tablet computers (and smart phones) can connect to the Internet through a wireless phone service carrier or a local wireless network. This flexibility is important, especially if the wireless data plan restricts the amount of data that can be downloaded. The availability of these devices and the low cost of Internet connectivity have made mobile commerce possible on a large scale for the first time. Leading online business research firms, including Forrester, Coda, and ABI Research, estimate mobile commerce to be about 81 billion today but expect rapid growth to levels between $ 10 billion and $ 30 billion by 2015