Short def: A brick wall.
Long def: Know Your Meme is a site that catalogs memes. The site is infested with weeaboos and shit-for-brains. Don't even think of voicing your opinion on there, or you'll get a sword down your throat. Yeah, their community is made up of those
people. What do I mean by them being a brick wall? I mean they won't listen. No matter how much you try to get your point across, they will not actually read it. At least not rationally. They pick what they want to read and use it against you. I've been on there.