A refrigerator used by 3 or more people, commonly found in apartments and office buildings. It is a dangerous place to leave food without some serious indication as to whose it is.
"I was hesitant to leave my leftover T-bell in the community fridge, but I had no choice."
"Hey man, I'm hungry. Wanna go raid the community fridge?"
Often arbitrary and nonsensical overbearing "rules" created and constantly changed by basement dwellers to take revenge on the world for always getting picked last at sports or the prom. Added to and made more oppressive weekly, or whenever the moderators run out of hot pockets.
Hey, that meme you posted was really Funny! Too bad you violated "Community Standards". 30 day ban.