I've seen many of interviews with "knowledgable" porn stars and they get tested for HIV about once a month or more. Also, I've heard from numerous ones that they keep their personal and professional lives in the insdustry, meaning that they date other pornstars. So as long as everyone is relatively clean, then you don't have much to worry about, you have sex with 100 people that are HIV neg, your obviously not going to catch HIV, The average normal person meeting someone in a bar is probably more at risk than they are.
I'm sure they're all HPV infected, and I agree it is likely that overt warts are a common occupational hazzard. But I'll also bet that they are on top of it and that expert treatment is readily available. At least herpes can be treated to prevent outbreaks and transmission, so I'm not sure what to predict about HSV-2 and genital herpes. My understanding is that the porn industry, at least in So. California, is pretty well organized and cognizant of the health risks, and that employers (and the health department) require regular HIV testing. I would guess routine testing for other STDs also is common. I can't comment on how much the workers themselves know, understand, or care about the risks.
Regards-- HHH, MD