This probably comes under the ‘no shit Sherlock’ category, but a recent study by Gadgetology found that one in five iphone users regularly watches adult material on their phone. What is interesting is that Blackberry users watched less than iphone users.
The reasons are probably varied: the iphone is highly usuable, and watching videos is an integral application. It may also be that Blackberry traditionally has a greater appeal to the business user, with many companies issuing the RIM handsets to their staff. Conversely an m:metrics study showed that 70% of iphone users are men, whereas the Blackberry has a 60:40% male:female ratio.
It does, however, help explain part of the appeal of the iphone. Historically many technologies have taken off where it has allowed users to access porn: VHS (in fact, the success of VHS over Betamax is often considered down to the porn industry adopting the former format), e-commerce, broadband. Even the now defunct Poloroid had an appeal to the home made-porn market.
The recent wide spread press coverage of iblushbabes, shows the sizable appetite for adult content on mobile phones.