10. An on-line comment management system, comprising: a hardware server; software executing on the hardware server, the software comprising: a content manager, operable on a computer server system that includes one or more processors, to provide content for review by users over a network; a ratings interface to receive, from the users, ratings on corresponding pieces of the content; and a ratings reviewer programmed to determine whether to review a particular rating from a particular user by performing a random selection that randomly selects particular ratings to review from among a plurality of ratings, wherein the determining comprises: selecting a number at random, adjusting the selected number up or down using results of prior reviews of ratings from the particular user, and determining, based on the adjusted number, whether to provide the first piece for review to determine whether the on-line content is legitimate or not, wherein a likelihood that the first rating is selected for review is influenced based at least on a measure of trust associated with the particular user, wherein the measure of trust is determined based at least on the results of prior reviews of ratings from the particular user, wherein the ratings reviewer is further programmed to maintain results, for each particular user, comprising a first bias for trusting a rating and a second bias for discarding a rating, and adjusting the first and second biases based on whether the review of the rating indicates that the rating was legitimate.
10. An on-line comment management system, comprising: a hardware server; software executing on the hardware server, the software comprising: a content manager, operable on a computer server system that includes one or more processors, to provide content for review by users over a network; a ratings interface to receive, from the users, ratings on corresponding pieces of the content; and a ratings reviewer programmed to determine whether to review a particular rating from a particular user by performing a random selection that randomly selects particular ratings to review from among a plurality of ratings, wherein the determining comprises: selecting a number at random, adjusting the selected number up or down using results of prior reviews of ratings from the particular user, and determining, based on the adjusted number, whether to provide the first piece for review to determine whether the on-line content is legitimate or not, wherein a likelihood that the first rating is selected for review is influenced based at least on a measure of trust associated with the particular user, wherein the measure of trust is determined based at least on the results of prior reviews of ratings from the particular user, wherein the ratings reviewer is further programmed to maintain results, for each particular user, comprising a first bias for trusting a rating and a second bias for discarding a rating, and adjusting the first and second biases based on whether the review of the rating indicates that the rating was legitimate. 13. The system of claim 10 , wherein the ratings reviewer is further programmed to apply to each particular rating a decision set comprising trust, discard, and review.