hobbyist-led development of interlinked computer networks using wireless LAN technologies, taking advantage of the recent development of cheap, standardised 802.11b (Wi-Fi) devices to build growing clusters of linked, citywide networks. Some are being used to link to the wider Internet, particularly where individuals can obtain unmetered internet connections such as ADSL and/or cable modem at fixed costs and share them with friends. Where such access is unavailable or expensive, they can act as a low-cost partial alternative, as the only cost is the fixed cost of the equipment.
Such projects started to evolve in 1998 with the availability of 802.11 equipment, and are gradually spreading to cities and towns around the world. In mid-2002 most such networks have been still embryonic, with small groups of people experimenting and gradually interconnecting with each other and thus expanding the domain and utility of the networks. As of mid-2005, wireless community networks have become increasingly popular and exist throughout many cities. Such networks have a distributed rather than a tree-like topography and have the potential to replace the congested and vulnerable backbones of the wired internet in most places.
These projects are in many senses an evolution of amateur radio, and more specifically packet radio, as well as an outgrowth of the free software community (which in itself substantially overlaps with amateur radio), and share their freewheeling, experimental, adaptable culture. The key to using standard wireless networking devices designed for short-range use for multi-kilometre linkups is the use of high-gain antennas. Commercially-available examples are relatively expensive and not that readily available, so much experimentation has gone into homebuilt antenna construction. One striking design is the cantenna, which performs better than many commercial antenna designs and is constructed from a steel food can.
Most wireless community network projects are coordinated by citywide user groups who freely share information and help using the Internet. They often spring up as a grassroots movement offering free, anonymous Internet access to anyone with WiFi capability.