(Internet slang) A habitual poster on the /b/ - Random board on 4chan; a member of the /b/ community.
Quotations
See the citations page.
Etymology
From /b/ - Random, an imageboard on 4chan. It combines a humorously censored version of bastard with /b/, while rhyming with retard. /b/ itself derives its name from the fact that the first original board on 4chan was /a/ - Anime, which has since been interpreted as an alliterative practice, but b was simply the next imageboard and thus was named with the next letter in the alphabet.