About

This meme is an image macro sires based off of an every day object edited in Paint to make a point with a visual pun(usually a joke specifically for 4chan).

The classic 'this is a bad post' comprises of a picture of a fence-post with With a Hat and Mustache ,and the text "This Is A Bad Post" on it.

Derivatives

This Post Is irrelephant:
The main Spin-off to "This is a bad post" is "This post is irrelephant" saying that the post this image is attached to is 'irrelevant' combined with a picture of an elephant.

This is a bad thread, and you should FEEL bad:
Tho having extremely similar backgrounds and uses, It seems that it Is a separate idea all together. It originated from An episode of Futurama when Zoidberg said "Your musics bad and you should FELL bad"