In 1992, Moss founded DEFCON, which grew to become one of the most successful and influential hacker conferences in the world. Five years later, Moss founded Black Hat, a sister conference to DEFCON, that's a little more focused on corporate issues than DEFCON. Moss also served as a director at Secure Computing Corp., and at Ernst & Young in its Information System Security division. (In the interest of full disclosure, United Business Media, the parent company of InformationWeek, acquired Black Hat Inc. in 2005.)
No one could reasonably argue that Moss doesn't know the hacker community and mindset, nor that he doesn't have a solid grasp on the security challenges in IT.
Moss is good for this job because of his connections in the corporate IT security as well as the security research communities. Those connections could come in handy at various times during the next three years of his time on the council. Moss also understands how hackers (white and black hat) think, and how IT and applications can be bent, broken, and mangled to do unintended things.
They are all perspectives sorely needed in federal IT discussions.