Mobile phones have always been a very personal device. If a potential customer wants to keep their activities to themselves using a mobile is a safer place to do it. Especially in cases where PCs/Tablets at home are used by the whole family. When you get the erge and you have a device that can offer porn anytime of the day or night no matter where you are then impulse is of course a large part of any mobile purchase.
If you look at the amount of companies that are now putting real effort into their mobile offerings I think it's pretty obvious that people do consume porn on their mobiles. Then take a look at the amount of mobile affiliate programs that have grown at a rapid rate in the last few years and it's even more clear that there is money in mobile porn.
The big issue is the billing especially in the EU where the credit card is used a whole lot less than in the US. This will remain an issue for the foreseeable future as the carriers take so long to payout and want such a large cut for being in your value chain. Then you throw the regulators in the mix and you have a much larger list of risks to consider.
In short Smartphones these days are pretty much mini PCs the potential to earn big is there but the mobile ecosystem moves at a rapid pace so staying on top of it is not easy... but it is possible with the right resources at you disposal
