Since Pornask seems to be a hater I made a quick image to help him along...
I cannot claim to be an SEO guru but it seems the website names come up more often because there is less competition for them.
When I say competition I do not mean other SEO affiliate advertisers, I mean less natural competition for the keyword.
Look at my example, both the words rough and deepthroat are on pages having nothing to do with selling porn. Perhaps 5000 personal blogs contain both words on a single page when someone is talking about the movie and how rough the housing market is...
But the term Kamilla 18 is not going to be on those personal blogs as it is not a household name.