I do an informal experiment testing whether LessWrong karma scores are susceptible to a form of anchoring based on the first comment posted; a medium-large effect size is found although the data does not fit the assumed normal distribution & the more sophisticated analysis is equivocal, so there may or may not be an anchoring effect.
LW anchoring experiment: maybe
Full writeup on gwern.net at http://www.gwern.net/Anchoring