Netbooks are a rapidly evolving category of small, lightweight, and inexpensive laptop computers suited for general computing and accessing Web-based applications; they are often marketed as "companion devices", i.e., to augment a user's other computer access. Netbooks typically have less powerful hardware than larger laptop computers.
Some netbooks do not even have a conventional hard drive. Such netbooks use solid-state storage devices instead, as these require less power, are lighter and generally more shock-resistant, but with much less storage capacity (such as 8, 16, or 32GB compared to the 80 to 160GB mechanical hard drives typical of many notebooks/laptop computers). All netbooks on the market today support Wi-Fi wireless networking and many can be used on mobile telephone networks with data capability (for example, 3G). Mobile data plans are supplied under contract in the same way as mobile telephone. Some also include ethernet and/or modem ports, for broadband or dial-up Internet access, respectively.
A smartbook is a concept of a mobile device that falls between smartphones and netbooks, delivering features typically found in smartphones (always on, all-day battery life, 3G connectivity GPS) in a slightly larger device with a full keyboard. Smartbooks will tend to be designed to work with online applications. Smartbooks are likely to be sold initially through mobile network operators, like mobile phones are today, with a wireless data plan.