Project Wonderful took the best of both (automated auction for ads, but there's only one ad active at any given moment for any given ad slot so no targeting) but apparently it wasn't able to keep making enough money to stay around
IIUC this is how ads on 4chan work. I learned this during my brief foray into targeted merchandising (https://www.temporary-url.com/9CBFE). Everyone on a given board at a given time was seeing the same ads.
ComicAd Network exists solely to fill the gap PW left, I really need to get around to setting it up on my current comics project.