Noninformative prior distributions (distributions that play a minimal role in the posterior distribution), also referred to as vague, flat, diffuse, or uninformative, are used in Bayesian analysis “to let the data speak for themselves, so that inferences are unaffected by information external to the current data” [66,61].
http://plosone.org/article/info:doi/10.1371/journal.pone.0028478#article1.body1.sec2.sec3.sec7.p1

There was a formatting error in the text referring to page 61 of reference 66. The correct text is: "Noninformative prior distributions (distributions that play a minimal role in the posterior distribution), also referred to as vague, flat, diffuse, or uninformative, are used in Bayesian analysis “to let the data speak for themselves, so that inferences are unaffected by information external to the current data” [66]."