e621 refers to the popular image-sharing site focused on furry and anthropomorphic art, named after the food additive code for monosodium glutamate (MSG). In internet culture, the site's logo and name have become symbolic of the furry fandom at large, often appearing in memes regarding internet rabbit holes, 'culture shock' reactions, or community-specific inside jokes. The meme typically revolves around the site's massive database and its sophisticated tagging system, frequently used to highlight the vast and sometimes overwhelming nature of niche internet subcultures with a mix of irony and self-deprecation.