I've been following the site for about 9 months now, more out of a sense of amused bewilderment than a sense of belonging or anything else. I guess I just don't get it. I mean, sure they post some funny and/or interesting stuff on there, but the majority of it is the exact same content you find on any other funny picture/gif aggregation site. Some of the original content is pretty good, but some of it just leaves me scratching my head.
I got introduced to it by a friend's wife who apparently found a picture of me and my buddy on HMotB from when we were doing a Tough Mudder event together. After that, I started noticing people everywhere wearing KCCOs, BFMs, spreading the gospel of how apparently Bill Murray is the greatest actor of all time, etc. I finally started going to the site out of curiosity, and haven't quite been able to stop. I even ran into someone the other day at a bar wearing a BFM and bought them a drink, mostly because I was really hammered and found it amusing.
I really don't understand the rabid cult-like devotion some people have for it, but I have to say I do appreciate the part where hot chicks are constantly sending pics of themselves in their underwear to be posted on the site. Hump Day is pretty much the highlight of my week. The stuff with Nick Offerman is always hilarious too.