Nutpicking is a portmanteau of "nut" and "nitpicking," which was defined by Mother Jones editor Kevin Drum (thus it's sometimes called "Kevin's Law" or "Drum's Law"):
“”[I]f the best evidence of wackjobism you can find is a few anonymous nutballs commenting on a blog, then the particular brand of wackjobism you're complaining about must not be very widespread after all.
The practice of nutpicking is usually employed most frequently in political debates as a method of invoking a false equivalence or tu quoque where one side sifts through the blogs of people "on the other side" to hold up a nutty comment to say "you guys do it too!" The most common nutpicking tactic by conservatives is probably trolling through DailyKos comments or some Troofer site and pulling up references to "Bushhitler." When Teabaggers found out about nutpicking, they immediately accused those who noted the racist elements of the 'bagger movement as nutpicking. That is, just because you can find a (whole lot) of racist depictions of Barack HUSSEIN Obama on 'bagger signs at "protests," it's not representative of the movement in any way, which is not racist. Of course, this ignores the fact that the Teabaggers ran openly racist candidates like Carl Paladino and Tom Tancredo as well as a guy who liked to dress up as a Nazi on weekends.