One of Apple's major marketing themes is that Macs are less susceptible to viruses, Trojans, and other hacker attacks than Windows PCs. While that argument has yet to hold much sway with enterprise IT departments, it is causing the U.S. Army to add some Macs to its networks.
Lt. Col. C.J. Wallington, a division chief in the Army's office of enterprise information systems, says that the Army is adding Macs to make its networks harder to hack. Wallington said that making networks more heterogeneous might make it more difficult for attackers to compromise an entire group of computers.
Source: CIO Today, http://www.cio-today.com