Well, I don't know what you are trying to sell to your visitors from Germany and if I would buy it, but Germans usually have different tastes and likes as all other nationalities. There is no 'German man', people are just different.

However, there are some national peculiarities in most countries or regions of the world, but I don't think they are so important that they would have a larger effect on most things you want to sell.

One possibility is that you are trying to sell stuff that might be exciting for your visitors from the US, but is quite normal over here in Germany or Europe. Like a lot of US folks go all crazy when there is a nipple to see and they seem to think the end of the world is near, but actually nobody would care over here because you can see nipples everywhere. Also nudity is not such a big issue over here. So if you are trying to sell things like this it's quite likely that you won't attract much business from Germany or Europe.

Also buying porn in general is not such a big deal over here. You can find porn shops in every major city and they are not hidden somewhere in a dark part of the town. You'll find them right in the bright city centers and next to McDonald's. And every video rental store has its adult section where you can rent dvd and video along with your favorite block buster. Buying porn over the internet is more a matter of convenience or for guys who have to hide their homosexual strike or curiosity from their wifes.