Online Marketing in Japan?

When I was helping out figuring out what would be the best way to marketing the video game product online in Japan, I was disappointed I could hardly find any options.

I’m talking about something other than those banner ads, but what I’m talking about is thing like Facebook page system. For example, there’s big Japanese SNS mixi, but problem of their system is that their “community” system is nothing more than “group” feature of Facebook (which means, there is no expectation that the community is “official.”)

What people use in Japan to do these marketing? Is it because those are happening all in their mobile realm, that I can’t see them, because I can’t access to them? Or they don’t simply exist? Or perhaps, only way to get on any online media in Japan is to utilize some sort of agencies?

I’d appreciate if anyone with information enlighten me!