A person using a genre/character/show/topic specific picture, an "avatar", accompanying each post on 4chan, typically with the reaction image of the "avatar" relevant to the tone of the post.
Most "avatarfags" belong to an interlocked network of "shitposters".

These "shitposters" are able to circumvent forced anonymity of boards such as /b/ through a Chrome/Firefox extension, "4chan X". 4chan X users can access a network, "Namesync", to monitor ID's of the user's extensions and allow ID ascription.

The equivalent of being a "Tripfag", but only to people using 4chan X and connected to Namesync.

Groups of related "avatarfags" usually participate in "circlejerk" threads, threads where they are the major posters, and post pictures related to the overall theme of their avatars, e.g., furry circlejerks include furry porn and comics; MLP circlejerks include screenshots of the show, "My Little Pony: Friendship is Magic"; Anime circlejerks include mangas, doujin, and other discussions of anime.
1. "You avatarfags are the cancer that is killing /b/. SAGE"

2. "FUCKING AVATARFAGS SAGE SAGE SAGE"

3. "Guise, every time I refresh the front page all I see are avatarfags. Wat do?"
by Ciamar January 13, 2013
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