According to the Urban Dictionary, a pixel peeper is:
1) A digital photographer who magnifies photographs on the computer screen to critically evaluate image resolution at the pixel level. Commonly used as a derogatory remark to describe:
a) A photography n00b who erroneously believes that the quality of a digital camera is determined solely by the number of mega pixels.
b) Insecure troll who frequents digital camera forums to religiously proclaim how his/her camera pixel count is greater than yours.
c) Wanna be photographer who debates about pixel count all day but doesn't have the talent to take a half-decent photograph.
Talk about being nasty ;)
I for one, pixel peep all the time; not in the noob or troll way, before I archive my fresh shots, I always zoom in to 100% on screen on selected shots.
This is the only way I can be sure that the image is sharp and at the same time I look out for digital artifacts and blemishes.
What prompt me to do this test was after Chris Bing, a friend and Nikon die-hard; drop into my office yesterday.