I shall rate this community using my fandom-rating system, by rating what I consider the three parts of a fandom (canon, in this case the actual website; fans, actual KYM community; and fanon, the creations of the community) individually on a 1-to-10 scale, then calculating the mean of those three scores to find the score of the overall fandom.
Canon: 10/10 Know Your Meme is a great website for its actual purpose. It is very informative and well managed. The mods are very dedicated and I respect that.
Fans: 8/10 The KYM community is full of interesting people, and I'm glad that I'm part of it. It is the first website where I felt like I made an impact. I never felt like that on Memebase, and I want to thank you guys for that. However, there is one small thing that keeps this score from being a 10.
Fanon: 6/10 I hate the KYMtheon. It is the single only thing that keeps this site from being perfect for me. You desperately try to give yourselves something to make this community unique, but you don't have to. Thankfully, the comments and forums aren't entirely cancerous and there is some legitimately funny content on this site, but I just can't ignore the KYMtheon, and for that I need to give the community's creations a rather low score.
Overall score: (10+8+6)/3 ≈ 8/10, 10/10 if it had no Don worshippers.