1. A method of estimating the likelihood of a Wi-Fi enabled device being located within an estimated geographical area, the method comprising: identifying at least one Wi-Fi access point in range of the Wi-Fi enabled device based on signals received by the Wi-Fi enabled device transmitted by the at least one Wi-Fi access point; consulting a reference database to determine for the at least one Wi-Fi access point from which signals were received a last-known estimated position of each of the at least one Wi-Fi access point and time information associated with each of said last known positions for describing the age of each said last-known position relative to other information in the reference database; estimating a likelihood that the at least one Wi-Fi access point has moved from its corresponding last-known position based on a number of Wi-Fi access points from which signals were received and the associated time information; and inferring the likelihood of the Wi-Fi enabled device being located within an estimated geographical area based, at least in part, on the likelihood that the at least one Wi-Fi access point has moved from its corresponding last-known position.