I see quite a few of these sites mentioned below also own their .mobi counterpart.
The Top 20 Porn Sites Accessed By U.S. Smartphones, April 2008
Smartphone users love the Web: Some 58% of U.S. smartphone owners use the Web on their phones, versus 13% of the general mobile population, according to research firm M:Metrics. And on average, smartphone owners use the Web on their phones for almost five hours a month. What are they looking at? Mostly the same stuff they do on their computers: Google (GOOG), Yahoo (YHOO), MSN (MSFT), Myspace (NWS), ESPN.com (DIS), etc.
But not all that time is spent reading email or checking sports scores. Of the top 600 sites accessed by smartphones in April, and tallied by M:Metrics, a few dozen of them were XXX-rated.
Here's our questions: Where do mobile users find these sites? Few, if any, of the top 20 mobile porn sites are household names like Playboy or Penthouse -- the one we're most familiar with is YouPorn, which we calculated last month was the "X-rated YouTube." This is the "long tail" at work. (Fair warning: These sites, of course, are not work-safe.)