A good indication of how mainstream some elements of Japanese culture are in the U.S. is reflected in sales like the one pictured above.
In terms of what I see as Japan's long-lasting impact on other cultures up to this, I tend to see much of the obvious. Since I currently reside in Japan, it's a bit difficult for me to pick up on things which have had a subtle impact as I'm seeing through the eyes of the media rather than as someone residing in a country other than Japan.
The strongest influences that I believe Japan has had are those on popular culture. Mainly, I think they've shared their culture in these areas:
- Anime-style artwork and action. I've noticed that traditional comic book-style has been altered or supplanted in many ways by huge-eyed, tiny-chinned looks. Even when some looks aren't direct copies, many are distorted to fit a similar look. I don't think this is going away any time soon as it dovetails very nicely with the move in the West to infantilize everyone and everything popular. If you look around at trends, you'll notice that everything seems to be moving toward removing all signs of maturity from pop icons including body hair and hints of wrinkles. Also, most actors are considered physically most desirable if they fit the "Q-tip" ideal - big head, tiny body which is also a part of anime. While I realize big heads are a part of all cartoons, it wasn't the norm that long, skinny bodies sat were the norm before. It was usually big heads on stubby, funny bodies or huge grotesquely muscled ones. Anime-style suits this trend very well though I don't believe Japan is in any way responsible for the trend toward infantilizing people and promoting it as attractive or an ideal.
- Food culture. I think Japanese cuisine has only partially penetrated most cultures but it will continue to do so, though most likely in a modified format for each culture that adopts it. The main impediment right now to Japanese cuisine going completely mainstream around the world is a lack of a fast food equivalents with high name recognition and low prices. One of these days, someone is going to work out a formula for dumbing down the core cuisine and serving it up cheap and fast and it'll find even broader acceptance than it has already. I think the push to move away from meat and foods high on the food chain may aid this as soy-based foods will hold more and more appeal as long as they are modified to suit Western tastes.
- Karaoke. I think this is going to be around for awhile and, like sushi, will be something that is always going to be a part of the Western cultures though clearly it'll be more or less popular in certain areas.
- A greater sense of responsibility at a younger age. I've noticed that Japanese young people, while they tend to remain more dependent into adulthood, face their lives with a greater sense of personal and interpersonal responsibility. Their attitude is not as self-centered as you tend to see in the West. They don't address every experience with a "what's in it for me" attitude.
- Fiscal conservatism. The Japanese are world-class savers and expert at deferring purchases in cases where making them would require them to go into debt. They have extremely low credit card debt on a per capita basis. While you do have people blowing money on expensive name brand goods, you don't have them racking up debt to do it.
- Food portions and menu diversity. This is a point of culture which the West, and America in particular needs rather badly, but it's unlikely to make in-roads for a variety of reasons. First of all, diversity requires more time and effort and people in the States have seen food as something that should be gotten out of the way rather than labored over. However, I think that the tendency among most people to eat a mix of items in small portions is part of what contributes to longevity in Japan.