Yes, AdBrite does allow Adult Sites. You will need to operate out of their subsidiary company, however: Black Label Ads. They are the same company, only separate quadrants of their operation, catering to the Adult Ad marketplace. I currently run Black Label on all of my Sites and find that with the ability to approve/reject my ads, I am most assured of the content being distributed and thus enjoy it the best currently.

There is also...

Adultadworld
Juicyads
xxxwebtraffic
trafficjunky

And several others that are newly-formed and will take a little while to gain notoriety.

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Good luck in your decision!