The name of this protocol implies a leap forward above and beyond WiFi, yet the two protocols are really suited to different purposes. WiFi and its 802.11n successor are designed for the home and office networks. WiMAX has rather grander plans, which include the entire suburb, and maybe eventually the whole country.
Like any self-respecting protocol, WiMAX has its own IEEE 802.16 standard, and its own forum to boost its chances of widespread success. The WiMAX Forum describes the protocol as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL." This description provides the clue to the expected use of WiMAX in the real world. Wireless ISPs in other regions are already using the 802.16e version of the specifications and some local ISPs have declared their intent to migrate their proprietary networks across to WiMAX in the near future.
Despite network vendors' claims that WiMAX will solve most of the networking problems of the world, the truth is a little less far-reaching. Because users must share available bandwidth, the more users the less each will get, and similarly to DSL technology the maximum throughput is determined by distance. WiMAX is capable of a theoretical 70Mbps and 113km reach, but you can't have both maximums at once.
Wireless hot-spots are still likely to use WiFi, or an enhanced version such as 802.11n, with hot-spots inter-connected with WiMAX. The technology is looking particularly attractive to countries with limited or no investment in copper-cables, because the transmitters con be co-located on existing mobile phone towers, and can also be used effectively to backhaul cell phone traffic to the exchanges. Locally we can expect to see increased use of WiMAX to cover the "last mile" where there is either a lack of cable or where installing cable would not be cost effective.