Inappropriate Ad on Wiki

This was rather shocking to me, so I'd like to know: Why is there an advertisement for a "Roman Orgy" on Death Note Wiki? (Call of Roma One Click for a Roman Orgy! Click Now!) Are these advertisements approved by Wikia before they appear on a wiki? Is there any rating system used to pick what Advertisements appear on certain wikis, or can we expect to see an advertisement for a "Roman Orgy" on something like My Little Pony Wiki? I don't mean to sound rude, but this has me rather concerned and a bit ticked off.