I'd like to say that means performers but I'm sure it's intentionally vague in the document -- security clearance applications are big on screening for potential things that you could be blackmailed or bribed for. Extensive debt, gambling, and drug use are all on the form. http://www.military.com/veteran-jobs/security-clearance-jobs...
I went thru the process (a long time ago) and if you worked in pr0n (although I did not) an excellent way to fail a security check would be trying something like hiding your past employment from a hard core evang fundamentalist C.O. or something similar to that. Theoretically leading to an enemy agent blackmailing you to keep your past quiet if only you'll give him a photocopy of some document or a password or whatever. But if you already told security you were a sysadmin at nude-hackernews-posters.com or whatever then it would be REALLY hard to blackmail you about something that's already public knowledge...
If this line applies to the issue, you're OK: "The behavior no longer serves as a basis for coercion, exploitation, or duress."
