Bing enjoys the reputation as a fine porn surfer, and that alone is going to generate decent numbers.
Rather than run away from the reputation as a porn surfer, which we all know is disingenuous anyway, they may as well keep building on it and keep improving the porn searching.
Porn is one of those things that no one else is supposed to like, but, it's somehow OK if you watch it. The hypocrisy is annoying, and I'm just not believing that Microsoft never put any thought into how well Bing searched for porn. Of course they did, it's only sensible since they care about increase share, and it's a large market. They'd be negligent to dismiss it.
If someone comes out with a browser named "Porn Surfer", they'd get a quick jump in market share. Internet Explorer? Dull and prosaic. Firefox? Stupid. Opera? What's the connection? Safari? Same. Chrome? Why name it out of an ugly, shiny metal that tasteless people are attracted to?
Microsoft Porn Surfer. It's got a nice ring to it. Tie it into Bing, and make Bing ask questions like "The search results have returned some listings that are not adult material. Do you still want to view them?". And issue warnings when porn material is rated dull by other viewers, etc...
It's worth a shot.