How come Japanese/Chinese style forums are so different to those elsewhere?

This is something that I've been wondering for quite some time, and I expect is to do with some cultural difference. But why are the Japanese style forums so different to those in the rest of the world? I've noticed generally, the USA, UK, Australia, Europe and Middle East usually use standard forum software like vBulletin, Invision Power Board, phpBB, etc (nothing about what's used in Africa because I haven't seen any internet forums based there at this point in time). But in Eastern Asia, especially in Japan, they seem to have completely styles of forum software, usually with anonymity, simpler features and a sort of threaded layout found more in the 90s. Think 2Chan or such like, although that specific forum is more justified in that it's been around for a long time, and so active (about 2 million posts a day) that converting it to a different type of forum software would take in the realm of months and be rather prone to errors.

So yes, why don't I see as many forums based over there using vBulletin or the like? Why did these really simple types of forums catch on more over there?

 

Things like Discuss are more popular over there.

 

I know such forum software is popular over there, I'm just curious to why. I can't speak Japanese, so I can't really translate vBulletin then search for it to see what the reasons are, so does anyone know anything relevant about the culture that would make said forums more popular?

 

Maybe it's hard to find complex forum software with full translations, mods in their language, etc. Just a guess.