Wi-Fi is a marketing term of the Wi-Fi Alliance. It is used as an umbrella term for many of the standards developed by the Institute of Electrical and Electronics Engineers (IEEE). The names of some of those standards can be seen in marketing material and in instruction manuals. Perhaps the most widely seen is the more forgettably named 802.11n.
These standards are essential for the makers of wifi products. By implementing them they know their products will work with a huge number of other products made to the same standards. This lets specialists develop sophisticated products in the knowledge that they can fit into an existing market.
Due to that cooperation between large numbers of makers of wifi products, wifi systems are currently the most well developed wireless network technology for general purpose connectivity.
So in fact the term wifi as it is commonly used actually refers to a system of hardware, software and the standards that specify them. Such a system will often involve products from a number of makers.
The location of devices connecting using wifi needs to be less well-known and is less constrained than for wired devices. This latitude makes planning wireless networks easier and provides more location flexibility for users.
Wifi is in many cases the only practical means of providing mobile connectivity. This is particularly true when devices need to range over large areas or cross regions of connectivity, such as site boundaries.
Wired networks are difficult or even impossible for some situations where wifi will work, such as environments with transient users.
Wifi connectivity can cover every point in large spaces inside and out, permanently or temporarily, and at a much lower cost than would be possible using only wired networks.
It is possible to find the position and track the movements of wifi connected devices.
Wifi allows for rapid switching between multiple connectivity routes for more dependable connectivity.
Wifi is adaptable for new uses because it provides general purpose wireless data transport, additional information about user position and devices, and extra dependability of connectivity. This has enabled it to be employed to supplement data transport by mobile phone networks and generate revenue in doing so. It is also used to provide advertising to users. The adaptability of wifi will likely mean other uses will be found for it.
Wifi can relatively easily manage changing numbers of devices. By contrast wired networks require much more infrastructure to be installed and managed to be as scalable.
A high density of connections in an area is easier to achieve with wifi than with wires because there are no physical limits imposed on wifi connections. By contrast wires and supporting infrastructure are space consuming and disruptive to install. This difference will become more important as greater numbers of connected devices come to pervade our environments.
The extra information available from wifi devices creates possibilities to increase security. Individual devices can be identified, tracked, and their connections analysed and controlled. It is also possible to restrict their access based on characteristics of software on the device and even to offer to improve them before granting access.