If you enjoy Tumblr's extensive selection of rape fantasy, underage girls, and women having sex with a variety of fauna, good news: Marissa Mayer just said she's keeping Tumblr NSFW.

If you're a potential advertiser, this might not be such good news, as there's no mechanism (yet) to prevent your branded content from appearing next to a girl choking on a dog's dick. Marketers try to avoid that sort of thing whenever possible, and it'll be a hump between here and profitability—there's a reason why Facebook keeps an iron wall up against "adult content."