Well there was a christmas comic a while ago where Neko got confused between Easter Jesus and Christmas Jesus, so we ended up with baby-on-a-stick. There's some religious stuff like that (it's pop culture that doesn't go stale!) and some sexual references and thinly-veiled drug references. It's nothing worse than Something Positive or Girls With Slingshots, which aren't blocked.
It could be there are just keywords in the blog that are being picked up, I might try setting up a DrunkDuck mirror which just has the comic on it.