Thanks for all your feedback, everyone.
We're looking into whether it's technically possible to have no links on sensitive topics - will get back to you as soon as we know more.
RockNRollNerd, we currently won't accept direct advertising from the following companies and types of company:
Payday loans, baby food marketed for babies under 6 months old, follow-on/formula milk, gambling, cosmetic surgery, Nestle (formula milk marketing in the developing world), publications like The Sun, Zoo and FHM which overtly objectify women, porn, and Seaworld.
We also have the following blocks in place for automatically served ads (Adsense/Adwords):
Bingo/lottery, casino/gambling, cigarettes/cigars/tobacco, dating, credit cards, weight loss, gaming/online/video games, guns/ammo/weapons, loans - home/mortgages/students/financial aid, medical - hospitals/plastic surgery/quit smoking, online videos, pharmaceuticals/drugs, religious, psychics, adult sites, virus scanner and credit reporting. And if we spot things we don't like the look of, or MNers report them, we'll block them reactively too.
Hope that helps - we'll get back to you on the Skimlinks questions as soon as we've got more info.