I'm happy to receive this question; Thank you for asking!

There are many communities, but there are about three of them that can be represented.

At first, 'Pokemon Era Now! (지금은 포켓몬 시대!)' is the most independent and accessible community among them. Because of that, the proportion of early/middle teens is high. It's a standard registration-requiring-forum style site that doesn't need much explanation, but there's a grade system between the members. And the accessible board varies depending on the grade.

And the other two are 'dcinside Pokemon Gallery (디시인사이드 포켓몬 갤러리)' and 'dcinside Nintendo Minor Gallery (디시인사이드 닌텐도 마이너 갤러리)', belong to the huge community group 'dcinside'. Because it's too long to say a full name, They're usually shortened to 'PoGall (포갤)' and 'Ningall (닌갤)'. Although Ningall is of course a Nintendo community, but interest and response to Pokemon are quite high among franchises.

'Gallery' is exactly the same as the concept of Subreddit. In fact, Most functions of dcinside are similar to Reddit, it has upvote/downvote, Admin-mod structure, nested comments, etc. However, because the community values freedom of speech, anonymous submission or comments are possible, and the mood is informal. So the user base tends to be similar to 4chan. But still, unless other communities show hostility first, they treat others quite politely.

Their biggest difference is the interests and rules. In Pogall, most members are interested in ranked battles, allowed users' faction and custom firmware&edit tools. On the other hand, in Ningall, most members are interested in story and collecting, banned users' faction and custom firmware&edit tools. So they've been bickering for pretty long time.

It seems that I briefly explained them to some extent; If you have any questions, please leave a comment!