There are four Window-Eyes licenses:
The Single User License is the most common and simplest to explain - it is either one person or one computer. It is most often a copy of Window-Eyes intended for one person. That person may own multiple computers with Window-Eyes installed on each of them and still purchase a Single User License. In this situation of course only that single person may use that copy of Window-Eyes. There is one alteration of the Single User License and that is the situation often found in a public school with one adapted computer but multiple students sharing that one computer. In this situation only one student at a time may use the computer.
A Site License for Window-Eyes allows for the use on many computers by many simultaneous users. A site license is intended to be used in one physical location or one physical campus. For example, a college campus may purchase a site license. However, if there is a satellite campus on the opposite side of the city, a second copy or site license must be purchased. The most typical application of a site license is a computer lab. GW Micro sells site licenses in increments of 5 so you may purchase a 5-user, 10-user, 15-user etc. site license. If you have 8-users of Window-Eyes then you should purchase a 10-user site license. One CD is furnished with the Site License.
An Agency License is similar in some ways to a site license. The difference is that the locations may all be different but there must be one purchasing entity. An example of this would be a cooperative school system, where 4 counties work together to provide an itinerant teacher for students in various locations. One purchasing entity buys the copies of Window-Eyes but they are installed in several locations. The minimum initial purchase must be for 5 copies, but afterward additional single copies may be purchased. Multiple CDs are provided with an Agency License so if you purchase 5 Agency Licenses you will receive 5 CDs and 5 unique serial numbers. Upgrades may be purchased individually for each copy which means it is possible to own 5 Agency License but to purchase upgrades for three of them.
Wide Area Network (WAN) License
A Wide Area Network License (or WAN License) supports up to 5 users and is identical to the Agency License in every way except for the number of CDs and how it may be upgraded. A WAN License consists of one CD with one serial number. Typically the CD is held by an IT department who pushes the installs to individual computers or does some type of network install. Since there is one CD and serial number upgrades are sold to all users. This means a 10-user WAN License purchases 10 upgrades. A typical application of the WAN License would be an insurance company with employees around the world in various locations and perhaps using a Citrix/Terminal Services environment.