>/pol/
too big. Anything that starts on /pol/ is site-wide within a week and national news within a month.

>/b/
What culture lmao

>/v/
same as /pol/. Also they share culture with most several other large vidya boards like /vg/ and /vr/, making their memes common rather quickly

>/a/
same problem as /v/. Their culture has permeated so much of the site since its founding that its not really unique anymore. Important, yes. Bu not unique

>/k/
my personal vote for most unique. They share culture with pretty much no one. They have a user base big enough to develop their own memes but not so big that they leak all over the place. They keep to themselves for the most part, and their unique military and outdoorsy oriented memes makes a /k/ommando instantly recognizable anywhere they post.